What's the difference between Object.is() and the triple equals operator in JavaScript?

Angelos Chalaris · Mar 4, 2021 ·

JavaScript, Object, Type

If you want to check equality in JavaScript, there are two comparison operators, which are explained in depth in a previous article.

Very briefly, the double equals operator (==) only compares value whereas the triple equals operator (===) compares both value and type. But there is also a third option, Object.is(), which behaves the same as the triple equals operator with the exception of NaN and +0 and -0.

Here are some examples for additional clarity:

{} === {}; // false
Object.is({}, {}); // false

1 === 1; // true
Object.is(1, 1); // true

+0 === -0; // true
Object.is(+0, -0); // false

NaN === NaN; // false
Object.is(NaN, NaN); // true

Image credit: Jonathan Sanchez on Unsplash

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