JavaScript - check if number is even (Vanilla JS)

In this short article, we would like to show how check if number is even using JavaScript.

Quick solution:

if (number % 2 === 0) {
    // ...
}

Even numbers:

... -8  -6  -4  -2   0   2   4   6   8 ...

Practical example

// ONLINE-RUNNER:browser;

function isEven(number) {
	return number % 2 === 0;
}


// Usage example:

console.log( isEven(0) );   // true      // even
console.log( isEven(1) );   // false
console.log( isEven(2) );   // true      // even
console.log( isEven(3) );   // false
console.log( isEven(4) );   // true      // even
console.log( isEven(5) );   // false

console.log( isEven(-1) );  // false
console.log( isEven(-2) );  // true      // even
console.log( isEven(-3) );  // false
console.log( isEven(-4) );  // true      // even
console.log( isEven(-5) );  // false

Alternative solution

In this section, you can find solution that uses bitwise operator.

// ONLINE-RUNNER:browser;

function isEven(number) {
	return (number & 1) === 0;
}


// Usage example:

console.log( isEven(0) );   // true      // even
console.log( isEven(1) );   // false
console.log( isEven(2) );   // true      // even
console.log( isEven(3) );   // false
console.log( isEven(4) );   // true      // even
console.log( isEven(5) );   // false

console.log( isEven(-1) );  // false
console.log( isEven(-2) );  // true      // even
console.log( isEven(-3) );  // false
console.log( isEven(-4) );  // true      // even
console.log( isEven(-5) );  // false

See also

1. JavaScript - check if number is odd (Vanilla JS)