The == Operator Lacks Transitivity in JavaScript

In mathematics “is equal to”, equality is a transitive relation meaning that

if a = b and b = c, then a = c

Be aware that the == operator lacks transitivity in JavaScript.

Consider the following example where a = '0', b = 0 and c = ''

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

Don’t use the == operator, use the === operator for equality instead.

'0' === 0   //false 
 0  === ''  //false
'0' === ''  //false