== (equal) vs === (strict equal) in javascript which is faster?

javascript is not strictly typed language which means you can simply define a variable without declaring its type that plays an important role in comparison

js have two options for variable comparison

1. == : this checks for values of variable

for eg.

let a = "5";
let b = 5;
console.log(a==b) //prints true

2. === : checks for value as well as the datatype of a variable since in the above example ais of type string and b is of type number it prints false

so what exactly happens when you try to use == and which is the faster? and which one to use?

when you use == it does coercion of datatype and converts them into one possible datatype then it compares for the value

in the above example, it tries to convert b into a string there are different coercion rules which you can learn more from here: https://developer.mozilla.org/en-US/docs/Glossary/Type_coercion

since == has to do coercion underneath before comparison whereas === returns false as soon as it encounters conflicting datatype

performance test from jsbench: https://jsbench.me/qqkl51rx8v/1

conclusion: Always use 3 equals unless you have a good reason to use 2. it’s always good to use predefined datatypes even though js is very forgiving by nature