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This method was introduced in ES2015. It aims to help comparing values.

Usage:

Object.is(a, b)

The result is always false unless:

  • a and b are the same exact object
  • a and b are equal strings (strings are equal when composed by the same characters)
  • a and b are equal numbers (numbers are equal when their value is equal)
  • a and b are both undefined, both null, both NaN, both true or both false

0 and -0 are different values in JavaScript, so pay attention in this special case (convert all to +0 using the + unary operator before comparing, for example).