freeCodeCamp/guide/english/javascript/standard-objects/object/object-is/index.md

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Object Is

Object Is

Description

The object.is() method is used to determine if two values are the same value. This method was introduced in ES6.

Syntax

Object.is(val1, val2)

Parameters

val1 - first value to compare

val2 - second value to compare

Return value

A Boolean indicating whether the two arguments have the same value

Description

Object.is() compares two values for sameness, returning true if both values meet one of the following conditions:

• undefined
• null
• Both true or both false
• String of the same length and same characters
• Same object
• Both numbers and:
  • Both +0 or both -0
  • Both NaN
  • or both a number that is not zero and not NaN

Examples

Object.is('string', 'string'); // true
Object.is(undefined, undefined); // true
Object.is(null, null); // true

Object.is('string, 'word'); // false
Object.is(true, false); // false
Object.is([], []); //false  

var obj = {name: Jane};
Object.is(obj, obj); // true

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

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

More Information:

Object.is() MDN Web Docs
Strict equality operator ===