Differences between ==, === and Object.is() in JavaScript

== Loose Equality

The == operator performs type coercion before comparing values

• console.log(1 == "1"); // true

• console.log(0 == false); // true

• console.log(undefined == null); // true

=== Strict Equality

It doesn’t perform type coercion or value conversion, but there are two notable behaviors to be aware of:

• console.log(+0 === -0); // true

• console.log(NaN === NaN); // false

Object.is() Same-Value Equality

As the name suggests, it compares if two values are the same. Despite starting with “Object”, it can compare any two values.

Unlike ===, Object.is() handles the special cases of zero and NaN differently:

• console.log(Object.is(+0, -0)); // false

• console.log(Object.is(NaN, NaN)); // true

Reference

What Is the Difference Between ==, === and Object.is in JavaScript?｜ ExplainThis