Which equals operator (== vs ===) should be used in JavaScript?

Double equals (==) is abstract equality comparison operator, which transforms the operands to the same type before making the comparison. 

For example,

5 ==  5       //true
'5' == 5      //true
5 == '5'      //true
0 == false    //true

Triple equals (===) are strict equality comparison operator, which returns false for different types and different content.

For example,

5 === 5  // true
5 === '5' // false
var v1 = {'value':'key'};
var v2 = {'value': 'key'};
v1 === v2 //false

Nancy Den

Updated on: 07-Jan-2020

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