JS: Object.is

New in ES2015.

Object.is ( value1, value2 )

similar to value1 === value2, except when values are signed zeroes and NaN.

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

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

Reference

ECMAScript 2015 §Fundamental Objects#sec-object.is