JavaScript .is()

The .is() is a static method in JavaScript used to verify that two values are identical. This method returns a boolean value. It returns true if both values have the same type and value, and false otherwise.

Syntax

The syntax of this method can be shown as below:

Object.is(val1, val2)

It takes two parameters. val1 and val2 that represent the first and second values.

Example

The Object.is() method has a special case for -0. Although -0 is identified as a number, it is not the same as +0 or 0. While 0 and +0 are treated as the same.

let num_zero = 0,
  num_zplus = +0,
  num_zmin = -0;

console.log(Object.is(num_zmin, num_zplus));
console.log(Object.is(num_zmin, num_zero));
console.log(Object.is(num_zero, num_zplus));

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The example above will return the following output:

false
false
true

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