Difference between '==' and '===' in JavaScript.

what is '==' ?

Double equals (==) is a comparison operator, which transforms the operands having the same type before comparison. In the example given below, '1' is a string but as we used == it converts the string to a number and returns true.

1 == '1'// true

'' == '0'           // false
0 == ''             // true
0 == '0'            // true
false == undefined  // false
false == null       // false
null == undefined   // true

what is '==='?

=== is used for comparing two variables, but this operator also checks the datatype and compares two values. It is more strict than ==.

1 === '1'// false
1 === 1 //true

key differences

• == Checks the equality of two operands without considering their type whereas === checks the equality along with their datatype.

• == checks for equality only after doing the necessary conversion whereas === directly takes the type and compares it without any conversions.

Conclusions:

1. == means: when we compare a number to string it, like 1 = '1' it will tell the string '1' that you are a number and return true.

   

2. === means: it is just a strict form of the operator where it considers the value as well as the data type.