javascript one line if assignment

Clean One-Line JavaScript Conditionals

August 12, 2021 - 3 minutes read

Writing shorter conditionals in JavaScript, when appropriate, can help keep our code concise yet clean.

I will demonstrate three different shorthand JavaScript conditionals:

Condensed if...else block

One-line ternary expression

One-line binary expression

Link to this section Condensed if…else block

Here’s a standard if...else block in JavaScript:

And here’s one way it can be shortened into a single line:

It’s worth mentioning this method also works for else if and else conditions like this one:

Just place each condition on its one line:

However, there is a caveat to this approach .

Consider the following code:

It won’t work. If you’re going to use this type of one-line conditional as the body of an ES6 arrow function , then you’ll need to enclose it in brackets:

Link to this section One-line ternary expression

JavaScript’s ternary expression is a much more versatile one-line conditional. However, it only supports if and else conditions (but not else if conditions).

Here’s a typical block of code using an if and else condition:

Here’s an example of shortening that block using a ternary expression:

A ternary expression contains two special symbols, “ ? ” and “ : ”.

These two special symbols separate the expression into three parts:

The code before the ? is the condition.

The code between the ? and : is the expression to evaluate if the condition is truthy .

The code after the : is the expression to evaluate if the condition is falsy .

Ternary expressions can be used in variable assignments:

And they can also be interlopated within strings:

Link to this section One-line binary expression

Now this is the one that I’ve found especially useful.

The binary expression only supports if conditions, but neither else if nor else conditions.

Here’s a typical if condition:

And here’s how we can use one of JavaScript’s binary expressions to shorten it:

This binary expression is separated by the “ && ” binary operator into two parts:

The code before the && is the condition.

The code after the && is the expression to evaluate if the condition is truthy.

Link to this section Conclusion

You made it to the end!

I hope you find at least one of these shortened conditionals useful for cleaning and shortening your code.

Personally, I use them all the time.

JavaScript One-Liner If-Else Statements

In JavaScript, you can have if-else statements on one line. To write an if-else statement on one line, follow the terna ry conditional operator syntax:

For example:

This is a useful way to compress short and simple if-else statements. It makes the code shorter but preserves the readability.

However, do not overuse the ternary operator. Converting long if-else statements into one-liners makes your code verbose.

The Ternary Operator – One Line If-Else Statements in JavaScript

Writing a one-line if-else statement in JavaScript is possible by using the ternary operator.

Here is the syntax of the one-liner ternary operator:

For instance, let’s say you have an if-else statement that checks if a person is an adult based on their age:

Running this code prints “Adult” into the console.

This code works fine. But you can make it shorter by using the ternary operator.

This way you were able to save 4 lines of code. And the code is still readable and clear.

Nested One-Line If…Else…Else If Statements in JavaScript

Trying to express everything in one line is no good. The ternary operator should only be used when the code can be made shorter but the readability remains.

However, JavaScript allows you to construct nested ternary operators to replace if…else…else if statements.

This corresponds to:

For instance, you can convert an if…else…else if statement like this:

To an expression like this using the nested ternary operator:

However, you already see why this is a bad idea. The nested ternary operator only makes the code hard to read in this example. Using the ternary operator this way is ineffective.

In this situation, you have two options:

• Use a regular if…else…else if statement instead of a nested ternary operator. That is still perfectly valid JavaScript code!
• Break the nested ternary operator into multiple lines.

Let’s next understand how the latter option works.

Multi-Line Ternary Operator in JavaScript

Your motive to use the ternary operator is probably to express if-else statements as one-liners. But it is good to know you can break a ternary operator into multiple lines too.

As you already saw, the one-liner ternary operator syntax in JavaScript is:

But you can break this expression into multiple lines this way:

Breaking the expression to multiple lines works with nested ternary operators too.

Generally, this type of nested ternary expression:

Becomes a multi-line ternary expression:

Let’s see a concrete example of this by going back to the example of checking the age of a person:

This ternary expression is rather verbose. Assuming you do not want to put it back to a regular if…else…else if statement, you can break it down to multiple lines:

However, it is up to debate whether this makes the code any better than the original if…else…else if statement. Anyway, now you know it is possible.

Be Careful with the Ternary Operator

Your goal is to always write readable and concise code.

Even though the ternary operator is a built-in mechanism, you can treat it as a “trick in a book”.

If you want, you may use the ternary operator to replace basic if…else statements with one-liners. However, avoid increasing the code complexity by replacing longer if…else…else if statements with one-liners. It is more than fine to use regular if…else statements in your code!

If you still want to use a lengthy ternary operator, please make sure to at least break it down into multiple lines.

In JavaScript, you can turn your if-else statements into one-liners using the ternary operator. The ternary operator follows this syntax:

For instance:

JavaScript also supports nested ternary operators for if…else…else if statements. This way you can have as long chains of ternary operators as you like.

Usually, a nested ternary operator causes a long one-liner expression. To avoid this, you can break the ternary operator down into multiple lines:

Keep in mind that using a one-liner if-else statement makes sense if it improves the code quality! Applying it on a complex if…else statement does not make sense as it decreases the code quality.

Here is a “good” example of a rather bad usage of the ternary operator:

Thanks for reading. Happy coding!

Slim Down Your Code with Single-Line Conditionals

January 23, 2016.

Reading time ~8 minutes

So you’ve been programming in JavaScript for a little while now. Your code is getting lean and mean and DRY as a California reservoir. Maybe you’ve even started to take advantage of some of JavaScript’s single-line conditionals and you’re wondering just how deep this rabbit hole goes. Maybe you have no idea what I’m talking about when I say “single-line conditionals”. Whether you’re a doe-eyed newbie or a hardened professional, this post has some fun tricks you may be interested in.

Braces Optional

The traditional way to write an if statement looks something like this:

This is all fine and good, sticks to practices we’re used to, makes a lot of sense. But what if we only have a single line of code in between those brackets?

Three lines of code for what amounts to one simple if/then statement? I don’t know about you, but this is starting to feel downright wasteful. Well, the fix in this case is rather simple. Just kill the braces:

This is a totally valid JS statement and will execute just fine. Anytime an if is not followed by curly braces, JavaScript will look for the next statement, and consider that the then part of your conditional. Even better, since whitespace is ignored, let’s kill that too:

BAM! Single-line conditional. Not only is it less code, but by removing a bunch of extraneous braces, I think we’ve actually made our code more readable too. And what if our simple if/then has a simple else ? Not a problem, else works the same way:

Simple. Readable. Short. My favorite kind of code. Technically you can do the same thing with else if ’s too, though in that case I might add a bit of white space back in to help with readability. Of course, if your plan was if/else all along, there may be a better tool:

The Ternary Operator

The ternatory operator (so named because it takes three operands), is one of the more intimidating pieces of JavaScript syntax a new coder is likely to encounter. It looks strange and alien, and the way it works is sometimes profoundly unclear. However, if you really want to save space, you can write the above if else statement in one single line:

Frankly, I find that the ternary operator really hurts readability, and I generally avoid it for that reason. You could add some white space to help clear things up:

This is a debatable improvement, and no longer satisfies our single line desires. Why not just go back to an explicit if else at this point? Well, I usually do. BUT, there is a scenario in which there is no substitute for our ternary frienemy: assignment.

Unlike an if else statement, the ternary operator is an operator . That means you are free to use it to the right of an assignment statement, which would throw one heck of a syntax error if you tried it with if else . Though this isn’t necessarily any more readable than other ternary uses, it saves an amazing amount of code when you compare it to the alternative:

The Case For Defaults

It turns out that there are more operators we can press into service to make our conditionals cleaner. One common example is to use the logical OR ( || ) to create default values in functions. For example:

If you’ve never seen it before, this construct may be a little confusing, though it does read in a remarkably sensible way: “input equals input or five.” In other words, if there’s an input, input should be that, if not, it should be five. Just like with a ternary, the beauty of this set up is that we can put this conditional in places you couldn’t put an if statement. Like for instance, as part of the return statement:

Same effect. Less Code. More readable. And imagine the alternate version using if else . Might as well go back to punch cards at that point.

But how does this bizarre hack of the OR operator actually work? The secret is in how JavaScript handles logical operators. In the case of || , JS is trying to determine whether either of the two operands is “truthy”. As soon as it sees the first one is, there is no reason to bother with the second. So it doesn’t. Furthermore, JS never bothers converting a truthy value to true , or a falsey value to false . Why bother? If the first operand is truthy, just return it. If not, the truthiness of the second operand will determine if the overall expression is truthy or not. So don’t even check it, just return it and be done.

One big gotcha to watch out for here: be sure the value of input can’t be falsey value that you want to keep. In the above code for example, if we passed in an input of 0 , we would ignore it and return 5 . There are six falsey values, false , 0 , NaN , '' , undefined , and null , and if our input evaluates to any of them, our default will be returned. But if that is the sort of behvior you are looking for, you can really clean up your code this way. Does that mean we can use && to write single-line conditionals too?

Using && to Write Single-Line Conditionals

Similar to the logical OR, && checks to see if either of two operands is falsey . If the first operand is, there is no point in checking the second. This behavior is not taken advantage of nearly as often as || , but I did just write some actual server code that I couldn’t have been done any other way:

The above helper function may seem a little daunting out of context, so allow me to offer a brief explanation. Using an array of users defined elsewhere, I am creating a series of User objects in my database. The order is important here, so I can’t iterate through users with a simple for loop. If one User happens to be slow to save, the next one would end up being created first. Not good. By using a recursive function I can ensure that each iteration will wait for the one before it.

And what about that insane (read: beautiful) single-line base case? I might have written it more clearly (read: uglily) like this:

If you’ve never seen this usage before, a return statement is a handy way to break out of a function. No more code will be executed once you run that return . It’s perfect for a recursive base case. Even better, if you need to call a function on your way out, rather than write them on seperate lines, you can just return the function call itself. So I might have used my own curly brace lesson from before and written:

But, I have one more problem problem. This helper function can be called in both asynchronus and synchronus environments, and so I do not know ahead of time whether or not next will be defined. The typical construct for calling a function only if it exists is the simple and readable if (fun) fun(); , but if you tried to return if (fun) fun(); , you would be rewarded with a big fat syntax error. Why? Remember, if and else are a statements , ?: , || , and && are operators . You cannot return a statement. But you can return the results of an operation. Which brings us back to my original implementation:

If next is undefined, JavaScript has no need to evaluate next() , and will simply skip it, returning the value to the left ( undefined , which is fine for my purposes). On the other hand, if next is a function (and therefore truthy), JS will look at the value on the right, see that there is a function that needs to be executed, and do so. A fairly complex series of operations have been reduced to one simple (okay, not that simple) line.

With Great Power…

To me, JavaScript is the ultimate “eh, sure I guess”, language. Can I just call undefined false? “Eh, sure I guess.” Can I get rid of these curly braces? “Eh, sure I guess.” What about this OR operator, seems like I could use it to set a default value. “Eh, sure I guess.”

That sort of flexibility can be very freeing, but there are pitfalls too. Remember that human beings still need to read your code. Before I pull out any of these tricks I always try to ask myself: does this make my code cleaner or messier? Does it make it more or less readable?

Shorter is nice, but clearer is better. It’s when you have the opportunity to do both that these tricks really shine.

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How to create one-line if statements in JavaScript self.__wrap_n=self.__wrap_n||(self.CSS&&CSS.supports("text-wrap","balance")?1:2);self.__wrap_b=(r,n,e)=>{e=e||document.querySelector(`[data-br="${r}"]`);let o=e.parentElement,l=u=>e.style.maxWidth=u+"px";e.style.maxWidth="";let s,i=o.clientWidth,p=o.clientHeight,a=i/2-.25,d=i+.5;if(i){for(l(a),a=Math.max(e.scrollWidth,a);a+1 {self.__wrap_b(0,+e.dataset.brr,e)})).observe(o)};self.__wrap_n!=1&&self.__wrap_b(":R4p4sm:",1)

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One-line if statements in JavaScript are solid for concise conditional execution of code. They’re particularly good for simple conditions and actions that can be expressed neatly in a single line. We’ll go into more detail on all of this below.

What is the basic if statement?

Before diving into one-line if statements, you should know the basic if syntax:

Use the one-line if without curly braces

For a single statement following the if condition, braces can be omitted:

Employ the ternary operator for if-else

The ternary operator is the true one-liner for if-else statements:

Combine methods or operations

Chaining methods or operations in a one-liner if statement can keep your code terse:

Leverage short-circuit evaluation

Short-circuiting with logical operators allows if-else constructs in one line:

Handle assignment within one-line if

You can assign a value based on a condition in one line:

Use arrow functions for inline execution

Incorporate arrow functions for immediate execution within your one-liner:

How to handle multiple one-line if statements

When dealing with several conditions that require one-liners, ensure they remain readable:

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Use one-liners in callbacks

One-liners can be effectively used within callback functions:

Know when to use if vs. ternary operator

The ternary operator is concise but use a regular if when the condition or actions are too complex for a ternary to remain clear.

Consider one-liners for default values

A one-liner if can set a default value if one isn't already assigned:

Be careful with one-liners and scope

Understand the scope of variables used in one-liners to avoid reference errors:

Remember operator precedence

When using logical operators in one-liners, keep operator precedence in mind to avoid unexpected results:

Avoid using one-liners for function declarations

Defining functions within one-liners can lead to readability and hoisting issues:

Use one-liners with template literals

Template literals can make your one-liners more readable when dealing with strings:

Understand limitations with const

Remember that const declarations cannot be used in traditional one-line if statements due to block-scoping:

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JavaScript One-Liner If-Else: The Ternary Operator Unleashed

Ah, the humble if-else statement: the bread and butter of decision-making in programming. But what if I told you that you could shrink that chunky if-else into a sleek one-liner? Enter the ternary operator, JavaScript’s way to make conditionals concise and sometimes even a bit cryptic. Let’s dive into how you can use this in your code to make it cleaner or just show off to your fellow devs.

What’s the Ternary Operator?

The ternary operator is like that one friend who always gets to the point. It’s a one-liner that has three parts: a condition, a result for true, and a result for false. It looks something like this:

Simple, right? It’s an expression, not a statement, which means it returns a value. That’s why you can use it in assignments, return statements, and more. Let’s see it in action:

Here, if isCoffeeTime is true, we’re brewing coffee. Otherwise, we’re coding away. The ternary operator is perfect for these quick decisions.

Ternary in the Wild: Real-World Examples

Assigning classes in react.

In React, you often need to dynamically assign classes. The ternary operator is your ally here. Imagine you have a button that needs to be highlighted when active:

This keeps your JSX clean and readable, without the need for a verbose if-else statement.

Conditional Rendering in Vue.js

Vue.js is all about simplicity, and the ternary operator fits right in. Say you want to display a message based on a user’s subscription status:

In one line, you’ve handled two different states. Vue-licious!

Setting State in Angular

Angular’s template syntax can also benefit from the succinctness of the ternary operator. Consider a scenario where you’re toggling a menu’s visibility:

Here, the ternary operator is used within the *ngIf directive to determine if the menu content should be rendered. Neat and sweet.

Quick Decisions in Svelte

Svelte aims to write less code and the ternary operator is perfectly at home in this framework. Let’s say you’re showing a user status:

The ternary operator makes it a breeze to conditionally render text in Svelte templates.

When Not to Use the Ternary Operator

While ternary operators are cool, they’re not always the best choice. If your logic is complex, using a ternary can make your code harder to read. Always prioritize clarity over cleverness. If you find yourself nesting ternaries, it’s probably time to step back and use a good old if-else statement or even better, a switch statement or a lookup object.

The ternary operator is a powerful tool in your JavaScript arsenal. It can help you write concise and readable code across different frameworks. Remember, though, with great power comes great responsibility. Use it wisely to keep your code clean and maintainable.

Stay tuned for the second half of this article, where we’ll dive deeper into advanced use cases and the nuances of the ternary operator. Until then, happy coding!

Advanced Ternary Operator Techniques

Now that we’ve covered the basics and seen the ternary operator in action with different frameworks, let’s step up our game. Advanced usage of the ternary operator can involve nesting (though, as warned before, tread lightly), using it for more than just assignment, and even some tricks that might just make you the wizard of one-liners.

Nesting Ternary Operators

Nesting ternary operators allows you to handle multiple conditions. However, it’s crucial to keep readability in mind. If you must nest, do it sparingly and format your code for clarity:

Here, each condition is clearly separated onto a new line, which helps maintain readability. But remember, if this starts to look like a tangled mess, consider a different approach.

Ternary as an Argument in Function Calls

You can use a ternary operator directly in function arguments to conditionally pass values without declaring them beforehand:

This can lead to more compact and inline code, especially when you’re dealing with simple conditions.

Immediate-Invoked Function Expressions (IIFEs)

For those times when you need an if-else with side effects, an immediately-invoked function expression (IIFE) can be combined with a ternary operator:

This pattern encapsulates the logic and executes it immediately, which can be handy in certain situations.

Logical AND (&&) and OR (||) with Ternary

Sometimes you might want to execute something only if a condition is true. This is where you can combine logical operators with the ternary operator for short-circuit evaluation:

Here, console.log('Show logout button') is only executed if loggedIn is true. Otherwise, the right side of the OR ( || ) operator is executed.

Ternary Operator for Object Property Access

You can use a ternary operator to conditionally access object properties without running into undefined errors:

This is particularly useful when dealing with objects that might have optional properties.

Best Practices and Pitfalls

When using the ternary operator, keep these best practices in mind:

• Clarity Over Cleverness : Always prefer readability over writing the shortest code possible.
• Avoid Deep Nesting : If you’re nesting more than once, consider refactoring your code.
• Format for Readability : If you use nested ternaries, format them in a way that makes the logic clear.
• Use for Simple Conditions : Ternary operators are best for simple, straightforward conditions.
• Comment as Needed : If the ternary makes a section of code less obvious, don’t hesitate to add a comment.

Wrapping Up

The ternary operator is a fantastic tool in JavaScript, allowing you to write concise and expressive code. Whether you’re working with React, Vue, Angular, or Svelte, it can help you keep your templates and scripts clean and to the point. Just remember to use it judiciously and never at the expense of the understandability of your code. Now go forth and ternary with confidence, but always keep the sage advice of “less is more” in your coder’s toolkit. Happy coding, folks!

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How to Use One-Line If Statements in JavaScript

When we’re knee-deep in code, every keystroke matters. As we strive for efficiency and readability, JavaScript’s one-line if statements rise as unsung heroes. They’re concise, potent, and enhance the elegance of our code.

Let’s imagine you’re navigating the labyrinth of JavaScript for the first time or you’re already a seasoned coder. Either way, you’ll find one-line if statements to be beneficial. They save precious time, reduce your lines of code, and make your scripts easier to understand.

In this post, we will be looking at the following 3 ways to use one-line if statements in JavaScript:

• By using the Ternary Operator
• By using the short-circuit evaluation with Logical AND Operator
• By using the short-circuit evaluation with Logical OR Operator

Let’s explore each…

#1 – By using the Ternary Operator

The ternary operator in JavaScript allows us to write compact, one-liner conditional statements. It checks a condition and returns one value if the condition is true, and another value if it is false. For example, a ternary operator can be used to decide which text to show based on a boolean value.

Here’s an example:

How it works

This one-line statement first checks if the isDay variable is true or false. If it’s true, it assigns the string “Good Morning!” to timeMessage. If it’s false, it assigns “Good Night!” to timeMessage.

Here’s the step-by-step explanation:

• The variable isDay is set to true.
• The ternary operator ? checks whether isDay is true or false.
• Since isDay is true, the expression before the colon (:) is returned, so “Good Morning!” is assigned to timeMessage.
• If isDay were false, the expression after the colon would be returned, so “Good Night!” would be assigned to timeMessage.

#2 – By using the short-circuit evaluation with Logical AND Operator

Short-circuit evaluation using the Logical AND Operator (&&) in JavaScript allows for executing a statement only if a certain condition is true. This works by leveraging how JavaScript evaluates the second operand in an AND operation only if the first operand is truthy.

In JavaScript, the logical AND (&&) operator short-circuits. This means that it stops evaluating as soon as it encounters a false or falsy value. If the first operand is truthy, only then the second operand is evaluated and executed. In the example above, the console.log statement is only executed if isAdult is true.

Here is a step-by-step explanation:

• Let’s assume isAdult is a variable representing whether a person is an adult or not.
• When the && operator is encountered, it first evaluates the expression on its left, i.e., isAdult.
• If isAdult is true (a truthy value), it then evaluates and executes the statement on the right. In this case, it will execute console.log(“You are allowed to enter!”).
• If isAdult is false (a falsy value), it will not evaluate and execute the statement on the right. Hence, nothing will be logged to the console.

#3 – By using the short-circuit evaluation with Logical OR Operator

In JavaScript, we can use logical OR (||) operator in a one-line if statement, where the first operand is a condition check and the second operand is an action that occurs if the condition is false. This technique is known as short-circuit evaluation and is handy for preventing errors when trying to access properties on undefined or null references.

Here is an example:

In this example, if x is undefined, null, 0, NaN, false, or an empty string, y will be assigned the string ‘Default value’ due to the short-circuit behavior of the logical OR operator.

• First, the JavaScript engine evaluates the expression from left to right.
• If the first operand (x in our case) can be converted to true, it short-circuits and returns the value of x.
• If x is falsy (i.e., it’s undefined, null, 0, NaN, false, or an empty string), it proceeds to the second operand.
• Since x is undefined in this code sample, the OR operator moves to the next operand, ‘Default value’, and assigns this value to y.
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In conclusion, one-line if statements in JavaScript, also known as ternary operators, make your code more compact and neat. It’s an efficient way to assign values based on conditionals, with less syntax and greater readability.

However, while they offer brevity, remember to use them judiciously to keep the code understandable and maintainable. Like any tool, their real power lies in knowing when and how to use them effectively, keeping the balance between simplicity and clarity.

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• JavaScript if...else Statement

The JavaScript if...else statement is used to execute/skip a block of code based on a condition.

Here's a quick example of the if...else statement. You can read the rest of the tutorial if you want to learn about if...else in greater detail.

In the above example, the program displays You passed the examination. if the score variable is equal to 50 . Otherwise, it displays You failed the examination.

In computer programming, the if...else statement is a conditional statement that executes a block of code only when a specific condition is met. For example,

Suppose we need to assign different grades to students based on their scores.

• If a student scores above 90 , assign grade A .
• If a student scores above 75 , assign grade B .
• If a student scores above 65 , assign grade C .

These conditional tasks can be achieved using the if...else statement.

• JavaScript if Statement

We use the if keyword to execute code based on some specific condition.

The syntax of if statement is:

The if keyword checks the condition inside the parentheses () .

• If the condition is evaluated to true , the code inside { } is executed.
• If the condition is evaluated to false , the code inside { } is skipped.

Note: The code inside { } is also called the body of the if statement.

Example 1: JavaScript if Statement

Sample Output 1

In the above program, when we enter 5 , the condition number > 0 evaluates to true . Thus, the body of the if statement is executed.

Sample Output 2

Again, when we enter -1 , the condition number > 0 evaluates to false . Hence, the body of the if statement is skipped.

Since console.log("nice number"); is outside the body of the if statement, it is always executed.

Note: We use comparison and logical operators in our if conditions. To learn more, you can visit JavaScript Comparison and Logical Operators .

• JavaScript else Statement

We use the else keyword to execute code when the condition specified in the preceding if statement evaluates to false .

The syntax of the else statement is:

The if...else statement checks the condition and executes code in two ways:

• If condition is true , the code inside if is executed. And, the code inside else is skipped.
• If condition is false , the code inside if is skipped. Instead, the code inside else is executed.

Example 2: JavaScript if…else Statement

In the above example, the if statement checks for the condition age >= 18 .

Since we set the value of age to 17 , the condition evaluates to false .

Thus, the code inside if is skipped. And, code inside else is executed.

We can omit { } in if…else statements when we have a single line of code to execute. For example,

• JavaScript else if Statement

We can use the else if keyword to check for multiple conditions.

The syntax of the else if statement is:

• First, the condition in the if statement is checked. If the condition evaluates to true , the body of if is executed, and the rest is skipped.
• Otherwise, the condition in the else if statement is checked. If true , its body is executed and the rest is skipped.
• Finally, if no condition matches, the block of code in else is executed.

Example 3: JavaScript if...else if Statement

In the above example, we used the if statement to check for the condition rating <= 2 .

Likewise, we used the else if statement to check for another condition, rating >= 4 .

Since the else if condition is satisfied, the code inside it is executed.

We can use the else if keyword as many times as we want. For example,

In the above example, we used two else if statements.

The second else if statement was executed as its condition was satisfied.

• Nested if...else Statement

When we use an if...else statement inside another if...else statement, we create a nested if...else statement. For example,

Outer if...else

In the above example, the outer if condition checks if a student has passed or failed using the condition marks >= 40 . If it evaluates to false , the outer else statement will print Failed .

On the other hand, if marks >= 40 evaluates to true , the program moves to the inner if...else statement.

Inner if...else statement

The inner if condition checks whether the student has passed with distinction using the condition marks >= 80 .

If marks >= 80 evaluates to true , the inner if statement will print Distinction .

Otherwise, the inner else statement will print Passed .

Note: Avoid nesting multiple if…else statements within each other to maintain code readability and simplify debugging.

More on JavaScript if...else Statement

We can use the ternary operator ?: instead of an if...else statement if the operation we're performing is very simple. For example,

can be written as

We can replace our if…else statement with the switch statement when we deal with a large number of conditions.

For example,

In the above example, we used if…else to evaluate five conditions, including the else block.

Now, let's use the switch statement for the same purpose.

As you can see, the switch statement makes our code more readable and maintainable.

In addition, switch is faster than long chains of if…else statements.

We can use logical operators such as && and || within an if statement to add multiple conditions. For example,

Here, we used the logical operator && to add two conditions in the if statement.

Table of Contents

• Introduction

Video: JavaScript if...else

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The if...else statement executes a statement if a specified condition is truthy . If the condition is falsy , another statement in the optional else clause will be executed.

An expression that is considered to be either truthy or falsy .

Statement that is executed if condition is truthy . Can be any statement, including further nested if statements. To execute multiple statements, use a block statement ( { /* ... */ } ) to group those statements. To execute no statements, use an empty statement.

Statement that is executed if condition is falsy and the else clause exists. Can be any statement, including block statements and further nested if statements.

Description

Multiple if...else statements can be nested to create an else if clause. Note that there is no elseif (in one word) keyword in JavaScript.

To see how this works, this is how it would look if the nesting were properly indented:

To execute multiple statements within a clause, use a block statement ( { /* ... */ } ) to group those statements.

Not using blocks may lead to confusing behavior, especially if the code is hand-formatted. For example:

This code looks innocent — however, executing checkValue(1, 3) will log "a is not 1". This is because in the case of dangling else , the else clause will be connected to the closest if clause. Therefore, the code above, with proper indentation, would look like:

In general, it is a good practice to always use block statements, especially in code involving nested if statements.

Do not confuse the primitive Boolean values true and false with truthiness or falsiness of the Boolean object. Any value that is not false , undefined , null , 0 , -0 , NaN , or the empty string ( "" ), and any object, including a Boolean object whose value is false , is considered truthy when used as the condition. For example:

Using if...else

Using else if.

Note that there is no elseif syntax in JavaScript. However, you can write it with a space between else and if :

Using an assignment as a condition

You should almost never have an if...else with an assignment like x = y as a condition:

Because unlike while loops, the condition is only evaluated once, so the assignment is only performed once. The code above is equivalent to:

Which is much clearer. However, in the rare case you find yourself wanting to do something like that, the while documentation has a Using an assignment as a condition section with our recommendations.

Specifications

Browser compatibility.

BCD tables only load in the browser with JavaScript enabled. Enable JavaScript to view data.

• Conditional (ternary) operator

One-Line If Statements in JavaScript

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Introduction

JavaScript conditionals are used to make decisions in code based on certain conditions. They allow code to execute different blocks of code depending on whether a condition is true or false. Writing concise and efficient code is important in any programming language, as it improves readability, maintainability, and performance. One-line if statements in JavaScript provide a solution for writing compact and streamlined conditional statements. In this article, we will explore the use of one-line if statements, their benefits, and various use cases.

The Ternary Operator

The ternary operator is a concise way to write if statements in JavaScript. It allows you to evaluate a condition and return one value if the condition is true, and another value if the condition is false. The syntax of the ternary operator is as follows:

The condition is the expression that is evaluated. If the condition is true, the valueIfTrue is returned. If the condition is false, the valueIfFalse is returned.

The ternary operator can be used as a replacement for simple if statements, providing a more compact and readable alternative. Here is an example to illustrate the difference between traditional if statement syntax and the ternary operator:

As you can see, the ternary operator allows you to achieve the same result in a single line of code, making your code more concise and easier to read.

Benefits of One-Line If Statements

One-line if statements offer several benefits that contribute to improved code readability, maintainability, and efficiency.

Improved code readability and maintainability

One-line if statements provide a concise and compact syntax, making the code easier to read and understand. By using a one-line format, developers can quickly identify the condition and the corresponding action without the need for excessive indentation or line breaks. This improves the overall readability of the codebase and makes it easier for other developers to understand and maintain the code in the future.

Reduction of code redundancy

One-line if statements help to reduce code redundancy by eliminating the need for repetitive code blocks. Instead of writing separate if and else blocks, developers can condense the logic into a single line. This reduces the amount of code that needs to be written and maintained, making the codebase more efficient and less error-prone.

Enhanced code efficiency and performance

One-line if statements can improve code efficiency and performance. With a concise syntax, the code execution time can be reduced, resulting in faster and more efficient code. Additionally, by avoiding unnecessary code blocks and reducing the overall size of the codebase, the application's performance can be enhanced.

By utilizing one-line if statements, developers can achieve more efficient and maintainable code, which ultimately leads to a more streamlined and effective development process.

Examples and Use Cases

One-line if statements in JavaScript can be used in a variety of scenarios to simplify code and make it more concise. Let's explore some examples and use cases for one-line if statements:

Basic Conditional Operations

One-line if statements are particularly useful for simple conditional operations. They provide a concise way to check a condition and perform an action in a single line of code. For example, consider the following code snippet:

In this example, we use the ternary operator to check if the age variable is greater than or equal to 18. If it is, the isAdult variable is assigned the value true , otherwise it is assigned the value false . This one-line if statement simplifies the code and makes it more readable.

Combining Multiple Conditional Statements

One-line if statements can also be used to combine multiple conditional statements and perform different actions accordingly. This is achieved by using logical operators such as && (AND) and || (OR). Here's an example:

In this example, we use nested ternary operators to check the temperature and assign the weather variable a value based on the temperature range. If the temperature is greater than 30, the weather variable is assigned the value "Hot". If the temperature is between 20 and 30, it is assigned the value "Warm". Otherwise, it is assigned the value "Cool". This allows us to handle multiple conditions in a single line of code.

Returning Values and Assigning Variables

One-line if statements can also be used to return values or assign variables based on a condition. This can be particularly useful when dealing with function returns or variable assignments. Here's an example:

In this example, we define a function isEven that takes a number as an argument and checks if it is even. The function uses a one-line if statement to return true if the number is even, and false otherwise. We then use another one-line if statement to assign the result variable the value "Even" if the number is even, and "Odd" otherwise. This allows us to handle the logic and assignment in a concise and readable manner.

These examples demonstrate the versatility and simplicity of one-line if statements in JavaScript. They allow us to write efficient and concise code, improving readability and maintainability. However, it is important to use them judiciously and maintain code clarity by avoiding excessively complex expressions.

Stay consistent with code style and formatting to ensure readability and make it easier for other developers to understand and maintain the code.

One-line if statements in JavaScript are particularly useful for handling basic conditional operations. They provide a concise and efficient way to perform a specific action based on a simple condition. Let's look at some examples that demonstrate their simplicity and ease of use.

In Example 1, we use a one-line if statement to check if the age is greater than or equal to 18. If the condition is true, the message "You are an adult" is logged to the console.

In Example 2, we assign the value of the canVote variable based on the condition age >= 18 . If the condition is true, the value assigned is "Yes", otherwise it is "No". This demonstrates how one-line if statements can be used to assign values based on conditions.

In Example 3, we show how to execute multiple statements based on a condition. If the age is greater than or equal to 18, the statements within the parentheses are executed, which in this case log two different messages to the console.

These examples highlight the simplicity and ease of use of one-line if statements for basic conditional operations. They allow you to write concise code that is easy to read and understand.

One-line if statements in JavaScript provide a concise and efficient way to combine multiple conditional statements. This can be achieved by using logical operators in conjunction with the ternary operator.

The ternary operator, also known as the conditional operator, allows us to evaluate a condition and return one of two values based on the result. It has the following syntax:

In the context of combining multiple conditional statements, we can use logical operators such as && (logical AND) and || (logical OR) to create complex conditions. The logical AND operator allows us to check if multiple conditions are true, while the logical OR operator allows us to check if at least one condition is true.

Let's take a look at an example to illustrate the use of logical operators with the ternary operator:

In this example, we have two conditions: age >= 18 and isStudent . We use the logical AND operator ( && ) to check if both conditions are true. If they are, the ternary operator returns the message "You are an adult student". Otherwise, it returns the message "You are not an adult student".

By combining multiple conditions with logical operators, we can perform different actions based on different sets of conditions. This allows for greater flexibility and control in our code.

It is important to note that when combining multiple conditions, we should ensure that the expressions are clear and easy to understand. Complex expressions can make our code difficult to read and maintain. Therefore, it is recommended to use parentheses to group conditions and improve readability.

In summary, one-line if statements in JavaScript provide a powerful way to combine multiple conditional statements by using logical operators with the ternary operator. This allows us to perform different actions based on different sets of conditions, resulting in concise and efficient code.

One-line if statements in JavaScript can be used to return values or assign variables based on a condition. This usage can simplify code and improve readability in certain scenarios.

Returning Values

One-line if statements can be used to return a value based on a condition. This can be particularly useful when a simple condition determines the value to be returned. Here's an example:

In this example, the one-line if statement checks if a number is even by using the modulo operator % to check if the remainder is zero. If the condition is true, the function returns true , otherwise it returns false . This approach allows for a concise and readable implementation.

Assigning Variables

One-line if statements can also be used to assign variables based on a condition. This can be helpful in situations where a specific action needs to be performed based on a condition, and the result of that action needs to be assigned to a variable. Here's an example:

In this example, the one-line if statement checks if a user is a premium user. If the condition is true, the discountPercentage variable is assigned a value of 0.2 , indicating a 20% discount. Otherwise, it is assigned a value of 0.1 , indicating a 10% discount. This approach allows for a concise and efficient way to assign variables based on conditions.

By using one-line if statements to return values or assign variables, code can be simplified and made more readable. It allows for the logic to be condensed into a single line, reducing code redundancy and improving overall code efficiency.

Best Practices

When using one-line if statements to return values or assign variables, it is important to maintain code clarity and avoid excessively complex expressions. Here are some best practices to follow:

• Keep the condition and actions simple: One-line if statements are most effective when the condition and the actions are straightforward. Complex conditions or multiple actions can make the code harder to read and understand.
• Use meaningful variable and function names: Clear and descriptive variable and function names can enhance code readability and make it easier to understand the purpose of the condition.
• Avoid nesting one-line if statements: Nesting multiple one-line if statements can lead to code that is difficult to follow. Instead, consider using a traditional if statement for more complex conditions.

By following these best practices, developers can ensure that their one-line if statements are effective, readable, and maintainable.

Remember, one-line if statements should be used judiciously and only in scenarios where they enhance code readability and efficiency.

When using one-line if statements in JavaScript, it is important to follow certain guidelines to ensure that your code remains effective and readable. Here are some best practices to consider:

Maintain code clarity: One-line if statements can be concise, but it is crucial to keep the code clear and understandable. Avoid writing overly complex expressions that can be difficult to decipher. Instead, opt for simplicity and readability.

Avoid excessively complex expressions: While one-line if statements can be powerful, it is best to avoid nesting multiple conditions or performing complicated operations within them. This can make the code hard to follow and troubleshoot. If your condition becomes too complex, consider using a traditional if statement instead.

Consistency in code style and formatting: Consistency is key to writing clean and maintainable code. When using one-line if statements, ensure that you follow a consistent style and formatting throughout your codebase. This makes it easier for other developers to understand and work with your code.

By adhering to these best practices, you can write effective and readable one-line if statements that enhance code clarity and maintainability in your JavaScript projects.

In conclusion, one-line if statements in JavaScript offer a concise and efficient way to handle conditional operations. By utilizing the ternary operator, developers can write code that is more readable, maintainable, and efficient.

One of the key benefits of one-line if statements is their ability to improve code readability. By condensing the logic into a single line, the code becomes more concise and easier to understand. This can be particularly useful for simple conditional operations where a full if statement would be unnecessarily verbose.

Furthermore, one-line if statements help reduce code redundancy. By eliminating the need for additional lines of code, developers can write more efficient and streamlined programs. This can lead to improved performance and a more efficient codebase.

One-line if statements also offer flexibility in combining multiple conditional statements. By using logical operators within the ternary operator, developers can perform different actions based on multiple conditions. This allows for more complex logic to be expressed in a concise and readable manner.

Additionally, one-line if statements can be used to return values or assign variables, further enhancing code readability. This approach simplifies code and makes it easier to understand the flow of the program.

In practice, it is important to follow best practices when using one-line if statements. It is crucial to maintain code clarity and avoid excessively complex expressions. Consistency in code style and formatting is also important for readability and maintainability.

In conclusion, utilizing one-line if statements can greatly improve the efficiency and readability of JavaScript code. By writing concise and efficient code, developers can enhance their productivity and create cleaner and more maintainable applications.

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One-Liner If-Else Statements

This is a common feature in many programming languages. Instead of writing an if-else on multiple lines, you can use the ternary operator to write the whole statement with one line of code.

For example:

However, do not overuse this. It can quickly make your code more verbose too. It is wise to replace only simple expressions with this to improve readability and reduce lines of code.

https://medium.com/geekculture/20-javascript-snippets-to-code-like-a-pro-86f5fda5598e

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javascript one line if else

Answered on: Monday 04 December, 2023 / Duration: 18 min read

Programming Language: JavaScript , Popularity : 9/10

Solution 1:

One-line if-else statements in JavaScript

One-line if-else statements in JavaScript are a concise way to write conditional code. They can be used to execute a block of code if a condition is true, or another block of code if the condition is false.

The syntax for a one-line if-else statement is as follows:

For example, the following code checks if the variable x is equal to 10. If it is, the code prints the message "x is equal to 10". Otherwise, the code prints the message "x is not equal to 10".

One-line if-else statements can be even more concise if the else block is empty. In this case, the else keyword can be omitted, and the statement can be written as follows:

For example, the following code checks if the variable x is equal to 10. If it is, the code prints the message "x is equal to 10". Otherwise, the code does nothing.

One-line if-else statements can be a very convenient way to write conditional code. They are especially useful when the conditional logic is simple and the else block is empty.

Code examples

The following code examples demonstrate how to use one-line if-else statements in JavaScript.

Example 1: Checking if a variable is equal to a value

The following code checks if the variable x is equal to 10. If it is, the code prints the message "x is equal to 10". Otherwise, the code prints the message "x is not equal to 10".

Example 2: Checking if a variable is greater than a value

The following code checks if the variable x is greater than 10. If it is, the code prints the message "x is greater than 10". Otherwise, the code prints the message "x is not greater than 10".

Example 3: Checking if a variable is empty

The following code checks if the variable x is empty. If it is, the code prints the message "x is empty". Otherwise, the code prints the message "x is not empty".

Example 4: Using an else if statement

The following code uses an else if statement to check if the variable x is equal to 10, 20, or 30. If it is equal to 10, the code prints the message "x is equal to 10". If it is equal to 20, the code prints the message "x is equal to 20". If it is equal to 30, the code prints the message "x is equal to 30". Otherwise, the code prints the message "x is not equal to 10, 20, or 30".

Solution 2:

Sure, in JavaScript, the one-line if-else statement (also known as the ternary operator) allows for concise conditional expressions.

The syntax is: condition ? expression_if_true : expression_if_false

Here's an example:

Explanation: - isRaining is a boolean variable set to true . - The ternary operator ? : checks if isRaining is true . - If isRaining is true , it assigns the string 'Bring an umbrella' to the weather variable; otherwise, it assigns 'Leave the umbrella at home' . - Finally, it prints the value of the weather variable, which in this case is 'Bring an umbrella' because isRaining is true .

This format is handy for simple conditional assignments and can be nested for more complex conditions.

Solution 3:

In JavaScript, an if-else statement can be written on a single line using the ternary operator. The syntax is as follows:

Here's an example of how to use this syntax:

In this example, we first declare a variable x and assign it the value 5 . We then use the ternary operator to check whether x is greater than 10 . If it is, the expression returns 'x is greater than 10' , otherwise it returns 'x is less than or equal to 10' .

Another example:

This time we are checking whether y is even or not by using modulo operator % and checking if the result is equal to 0 . If it is even the expression will return 'y is even' otherwise it will return 'y is odd' .

One more example:

In this example, we are checking whether the age is greater than or equal to 18 , if it is the expression will return 'You are eligible to vote' , otherwise it will return 'You are not eligible to vote' .

It's important to note that when using the ternary operator, the condition must be a boolean value (true or false). Also, keep in mind that this syntax is often used for simple conditional statements, but for more complex ones, it's better to use the regular if-else statement for readability purposes.

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How To Create and Use One-line If statement in JavaScript?

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One-line if statements allow writing conditional logic concisely in JavaScript . When used properly, they can make code more readable by reducing visual clutter.

Benefits of One-Line If Statements

• Avoid boilerplate code and nested indentation
• Improve readability for simple logic
• Prevent unintended scope changes
• Reduce noise and focus attention
• Concise syntax for frequent binary checks

Drawbacks to Consider

• Can reduce understandability if overused
• Limited to simple expression without blocks
• Lack support for else if and multiple branches
• Easy to introduce subtle bugs and mistakes

Ternary Operator If/Else

• Syntax options and variations
• Conditional (immediate) execution vs assignment
• Single expression vs full statement syntax
• Limitations and good use cases
• Examples including nesting ternaries

Logical AND If Statement

• Short-circuit evaluation behavior
• Truthy/falsy gotchas to watch out for
• Lack of else clause and empty statement
• Examples including default assignment
• Edge cases and cautionary tales

Logical OR If Statement

Multi-line if statement alternatives.

• Traditional if/else statements
• Switch case statements
• Immediately invoked function expressions (IIFEs)
• When to prefer multi-line conditional logic

Readability Best Practices

• Formatting guidelines for one-liners
• Limiting line length
• Comments for clarification
• Appropriate and judicious use
• Refactoring criteria and improving legibility

By the end of this deep dive, you’ll thoroughly understand the ins and outs of writing readable and robust one-line if statements in JavaScript. Let’s get started!

One-line if statements provide several advantages over standard multi-line conditional blocks:

Avoid Boilerplate Code and Nested Indentation

By collapsing if/else logic into a single line, one-liners avoid extraneous braces, indentation, and boilerplate JavaScript syntax.

This cleans up the appearance of simple conditional checks:

The reduction in visual clutter helps focus attention on the logic rather than the syntactic structure.

Improve Readability for Simple Logic

For straightforward true/false checks, one-line conditionals can actually improve readability over multi-line alternatives. The intent becomes more immediately clear.

By skimming for the binary operators like ? :, && and ||, you can quickly grasp simple conditional logic.

Prevent Unintended Scope Changes

Unlike multi-line if statements, one-liners don’t create a new nested lexical scope in JavaScript. This avoids issues when conditionally setting variables:

Reduce Noise and Focus Attention

Removing indentation, braces, and boilerplate focuses attention purely on the conditional logic. This forces you to distill conditionals down to their essence.

Concise Syntax for Frequent Binary Checks

For very common binary true/false checks, the compact operators ? : and && || provide convenient shorthand syntax. This reduces visual repetition.

However, one-liners also come with drawbacks, especially if overused.

While one-line if statements can help clean up simple conditionals, be aware of these potential downsides:

Can Reduce Understandability if Overused

Too many compact one-liners packed together make it harder to linearly scan and understand code. It becomes challenging to parse the program flow when scroll-reading.

Limited to Simple Expression Without Blocks

One-line conditionals only allow an immediate expression, not a full block with arbitrary logic. This forces code fragmentation into separate one-liners.

Lack Support for else if and Multiple Branches

Most one-line formats like ?: and && only offer simple if/else logic. Complex conditional chains require multi-line if/else instead.

Easy to Introduce Subtle Bugs and Mistakes

Omitting braces increases the risk of bugs when adding or modifying logic. It’s also easy to incorrectly assign instead of compare equality.

Not Always More Readable Than Multi-Line

Although one-liners remove visual noise, deeply nested and fragmented one-liners often become less readable than well-formatted multi-line conditional blocks.

Mixing One-Liners and Multi-Line Can Be Jarring

The constant switching between compact one-liners and multi-line blocks creates cognitive dissonance. It interrupts the reading flow when scanning code.

So while one-line if statements can help clean up simple checks, take care not to overuse them or force complex logic into compact syntax.

Now let’s explore specific one-line options starting with the ternary operator.

The ternary operator provides an inline way to evaluate if/else conditional logic:

Let’s break down the syntax:

• condition – Expression evaluating to true or false
• ? – Separator denoting start of if case
• exprIfTrue – Expression to execute if condition is truthy
• : – Separator between if and else cases
• exprIfFalse – Expression to execute if condition is falsy

This allows implementing if/else logic in a single line instead of multiple.

For example:

Ternary statements make great one-line shortcuts but also introduce complexity. Here are some nuances to understand:

Conditional (Immediate) Execution vs Assignment

The ternary operator is commonly used for conditional assignment to a variable:

However, it can also execute code conditionally without an assignment:

This provides a concise one-line if/else statement shorthand specifically for conditional execution, avoiding unnecessary temporary variables.

Single Expression vs Full Statement Syntax

By default, the ternary expects simple expressions in the if and else clauses:

But you can also execute multi-line statements using a comma operator:

This allows more complex logic while keeping the ternary syntax compact.

Limitations and Good Use Cases

The ternary operator only supports an if and else expression. It does not have else if or additional conditional branches.

So the ternary works best for simple binary checks and assignments, not complex multi-way logic. Good use cases:

• Toggle between two possible values like on/off, enabled/disabled etc
• Pick between two code paths conditionally
• Set a default value if a condition fails
• Initializing a variable based on a condition

Examples Including Nesting Ternaries

Here are some examples of using the ternary operator effectively:

Default Value Assignment

Conditional Console Output

Nested Ternary

Nesting ternaries allows implementing cascading if/else logic concisely. However, deeply nested ternaries rapidly become unreadable.

In summary, the ternary operator provides a compact inline syntax for basic conditional assignment and execution. Next, we’ll cover using logical operators && and || for one-line if statements.

The logical AND operator && can be used to execute a statement if a condition is truth:

This greets the user only if getUser() returned a valid user object.

Let’s explore how logical AND works and situational nuances to be aware of when using it in conditionals.

Short-Circuit Evaluation

The && operator uses short-circuit evaluation:

• Evaluates the left condition first
• If falsy, short-circuits and does NOT evaluate the right side
• If truthy, executes the right expression

This avoids needing to explicitly compare truthiness:

Short-circuiting makes logical AND ideal for optional chained calls like:

If user is falsy, the right side will not execute, preventing potential errors.

Truthy/Falsy Gotchas

Due to short-circuiting behavior, subtle bugs can occur based on truthy/falsy assumptions.

For example, this appears to check if cards contains any elements:

However, it will print the message if cards is truthy , even if it’s an empty array!

Instead, compare length explicitly:

So take care to properly check truthiness when using && in conditionals.

Lack of Else Clause

A drawback of logical AND is there is no else clause – it only executes the right side statement if the condition passes.

This limits it to straightforward binary true/false cases with a single expression. For anything more complex, use a full if/else statement.

Examples Including Default Assignment

Here are some examples of using logical AND effectively in one-line conditionals:

Check Empty Array

Default Assignment

Guarding Function Calls

Overall, logical AND provides a convenient compact syntax for executing expressions based on truthy conditions. But take care to properly handle truthy/falsy assumptions and edge cases due to lack of an else clause.

The logical OR operator || can serve as a concise one-line if statement as well:

This logs a message if the getUser() check returned a falsy value.

Logical OR works similarly to AND but with inverted behavior due to short-circuit evaluation:

• If truthy, short-circuits and does NOT evaluate the right side
• If falsy, executes the right expression

Next, we’ll explore nuances and cautionary tales when using || in one-line conditionals.

Due to short-circuiting, pay close attention to truthy/falsy assumptions.

This appears to log if user is null:

But it will execute the right side for any falsy value like 0 or empty string! Instead compare equality:

So double check truthiness assumptions when using || conditionally.

Similar to &&, logical OR does not have an else clause. It only executes the right expression if the condition is falsy .

There is no way to specify a second expression if the condition passes. This limits || for simple binary cases.

Here are some examples of using logical OR well:

Assigning Default Values

Providing Fallback Values

Conditionally Executing Code

In summary, logical OR provides a way to execute code or values based on falsy conditions. But use caution to avoid wrong assumptions due to truthy/falsy evaluations.

Now let’s look at some multi-line conditional alternatives.

For complex conditional logic, one-line statements may not provide enough flexibility. Some common multi-line options include:

Traditional if/else Statements

Regular if/else conditional blocks allow full control flow with else if and else branches:

The ability to check multiple conditions and choose between different code paths helps handle more complex logic.

Switch Case Statements

Switch case is useful when conditionally executing different code blocks based on discrete values:

The orderly cases and ability to fallthrough make switch well-suited for certain types of conditional logic.

Immediately Invoked Function Expressions (IIFE)

Wrapping conditional logic in an IIFE avoids leaking to the surrounding scope:

IIFEs allow using multi-line conditional logic without introducing variable hoisting issues.

When to Prefer Multi-line Conditionals

Consider using a multi-line conditional format if:

• You need  else if / else  clauses
• The logic is complex or verbose
• Code clarity is more important than brevity
• Scope issues exist with one-liners
• Mixing one-liners and multi-line becomes messy

Now let’s look at some readability best practices when using one-line conditionals.

To keep one-line if statements maintainable, consider these formatting and usage suggestions:

Break Lines on Operators

Consider breaking a long ternary operator over multiple lines:

Or break AND/OR logical statements:

This improves readability while keeping compact syntax.

Limit Line Length

In general, try to keep lines under 80 characters when possible by breaking conditionals across multiple lines.

Use Comments for Clarification

Add occasional comments above one-liners to document their intent if not immediately clear:

Use Braces for Complex Logic

If you need multiple statements in a conditional branch, use braces:

Don’t try to cram complex logic into a single statement.

Use Judiciously and Refactor

Resist overusing one-liners. If you have successive conditionals or deep nesting, consider refactoring to multi-line conditionals for better readability.

Appropriate and Judicious Use

In general, follow these guidelines for using one-liners judiciously:

• Reserve for simple true/false checks and assignments
• Avoid cramming complex logic into terse syntax
• Prefer multi-line conditionals for nested logic
• Only use when logic is immediately clear to the reader
• Refactor to multi-line if any ambiguity arises
• Document unclear one-liners with preceding comments
• Format for line length and readability

Err on the side of clarity rather than brevity.

Refactoring Criteria

Consider refactoring one-liners to multi-line conditionals if:

• They exceed 80 characters per line
• You need to scroll horizontally to read them
• There is nested conditional logic
• You are repetitively toggling between one-liners and multi-line
• Intermixing one-liners and multi-line becomes disjointed

The goal is to use the best syntax for overall code clarity and improve legibility. Ask yourself if expanding a one-liner to multiple clearly formatted lines would help or harm understandability.

The key takeaways:

• One-line if statements using ?:, && and || can improve compactness
• Avoid overusing terse one-liners at the expense of readability
• Stick to simple true/false checks rather than complex logic
• Prefer multi-line conditionals for nested clauses
• Use sensible formatting, line splitting, and comments
• Refactor code when one-liners become unreadable
• Ensure logic remains immediately clear to the reader

One-line if statements have appropriate uses for cleaning up trivial conditionals. But take care not to overuse them or obscure intent.

Prioritize code clarity through judicious use, formatting, and refactoring. The end goal is readable and maintainable software.

I hope this guide provides a thorough understanding of how to effectively leverage one-line if statements in JavaScript . Let me know if you have any other questions!

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• Python Guide

Declare Multiple Variables in a Single Line in JavaScript

By James L.

The most common way to declare multiple variables in JavaScript is to declare each variable individually on its own line.

For example:

However, there are times when you may want to group related variables together to provide a clear context of their usage. This is where declaring multiple variables on one line can be handy.

In JavaScript, there are several ways to declare multiple variables in a single line.

In this blog post, we will discuss the following methods:

Using comma separator

Using destructuring assignment with arrays and objects.

To declare multiple variables in JavaScript, you can use the var , let or const keyword followed by a comma-separated list of variable names, each initialized with corresponding values

var x = 5, y = 10, z = 15;

let x = 5, y = 10, z = 15;

const x = 5, y = 10, z = 15;

Avoid using var unless you absolutely have to, such as when supporting old browsers. This is because var variables can be redeclared and reassigned anywhere in your code, which can lead to unexpected behavior.

Do keep in mind that variables declared with the const keyword cannot be reassigned later in JavaScript. This means that their value cannot be changed once it has been initialized.

You can also declare multiple variables of different data types in a single line.

If you do not know the value of variables at the time of declaration then you can declare multiple variables using var or let keyword and assign their values later as follows:

However, you cannot use const keyword to declare multiple variables in one line and assign their values later.

This is because each variable created with const keyword must be initialized with a value at the time of declaration.

For example, this is not allowed:

Another way to assign multiple variables in JavaScript is to use the destructuring assignment, which allows you to unpack values from arrays or properties from objects into distinct variables.

Destructuring assignment makes sense when you have an array or object and want to extract its values to variables.

In general, it is best to declare each variable on a separate line, with its own assignment statement. This makes your code more readable and easier to maintain.

However, there are cases where it may be convenient to declare multiple variables on one line, such as when you are grouping related together, or when you are extracting values from an object or array using destructuring assignment.

Use single line multiple variable assignment sparingly.

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