This instruction is aimed to address your issues regarding JS falsy values from top to bottom. Having any query like that not yet resolved? This is indeed where you should drop your anchor to rack up the most.

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What Is JS Falsy Values?

To put it simply, something that evaluates to FALSE, such as when verifying a variable, is said to have a falsy value.

In JavaScript, the only valid false values are NaN, undefined, null, 0, “” (empty string), and, of course, false.

Follow these descriptions below to grasp better about those values.

• 0: The number zero (also counted as 0.0, 0x0, etc.)
• -0: The number negative zero (also counted as -0.0, -0x0, etc.)
• “”, ”, “: Empty string value.
• false: The false keyword.
• null: The lack of all values is null.
• NaN: not stated as a number.
• undefined: The fundamental value is undefinable.
• document.all: If and only if an object has the internal [[IsHTMLDDA]] slot, it is considered false. That slot is exclusive to documents.all JavaScript cannot be used to set any and.
• 0n: Large integer zero (also counted as 0x0n). The negation of 0n equals 0n, therefore take note that there is no BigInt negative zero.

JS Falsy Values – Example

False values’ examples in JavaScript that avoid the if block by being forced to true in boolean contexts include:

let string = ""; // falsy

let zero = 0; // falsy

let emptyArray = []; //  truthy

let emptyObject = {}; // truthy

You can see above the variables emptyArray and emptyObject that you used to learn in the first place. We think some of you may mistakenly think they are falsy values, because the array or object does not contain any value.

However, this is a truthy value. Truthy values are values that when converted to Boolean will be true, all values are truthy if they are not falsy values.

How To Check For JS Falsy Values?

For those who are in need of checking for JS falsy values, all you demand to do is merely adopt a simple conditional like this:

if (!variable) {
  // When the variable has a falsy value the condition is true.
}

When using falsy values with if and in combination with logical NOT (!), the value will convert to Boolean which is true, and so JavaScript will do the work in the if.

The Bottom Line

Now that you know what JS falsy values are as well as how to deal with it in particular circumstances, it is time to employ the resolving technique outlined above to carry out the most for your coding.

Hopefully, this in depth guide can be of great use to you as JS developer. Don’t hesitate to leave a comment and let us know if there are any concerns of yours not yet reached out. Good luck to you then!