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2 Quick Ways to Convert Values to Boolean in JavaScript πŸ’»

nialljoemaher profile image Niall Maher ・1 min read

The video version of this article. πŸ“Ή


Every so often you will find a situation where you will want to convert values to booleans.

This is more usual these days where most linters stop == comparisons by default.

Just as a quick note πŸ“

In JavaScript, we have "truthy" values and "falsy" values. These are values that are considered true or false in the context of booleans.

Here are the falsy values

// 0, -0 "", 0.0, null, undefined, NaN

And for truthy, it's pretty much everything else including empty Array and Objects.

Let's show you the easy ways to convert:

const falsey = NaN;
const truthy = "truth";

Boolean(falsey); // returns false
Boolean(truthy); // returns true

We can use ! (not) operator to invert a value into it's inverted state. So !truthy === false. So if we invert it twice we get the original value a boolean.

const falsey = NaN;
const truthy = "truth";
// bang bang, problem solved! πŸ₯³
!!falsey; // returns false
!!truthy; // returns true

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Niall Maher

@nialljoemaher

Owner @ CodΓΊ, JavaScript Developer, mentor and a lifelong learner. Tweet @nialljoemaher

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