JavaScript - Comparison

Comparison Operators

==	equal to	x == 8	false
		x == 5	true
		x == "5"	true
===	equal value and equal type	x === 5	true
		x === "5"	false
!=	not equal	x != 8	true
!==	not equal value or not equal type	x !== 5	false
		x !== "5"	true
		x !== 8	true
>	greater than	x > 8	false
<	less than	x < 8	true
>=	greater than or equal to	x >= 8	false
<=	less than or equal to	x <= 8	true

 

 

 

Comparing Different Types

 JavaScript will convert the string to a number when doing the comparison.

When comparing two strings, "2" will be greater than "12", because (alphabetically) 1 is less than 2.

2 < 12	true
2 < "12"	true
2 < "John"	false
2 > "John"	false
2 == "John"	false
"2" < "12"	false
"2" > "12"	true
"2" == "12"	false

 

 

 

The Nullish Coalescing Operator (??)

The ?? operator returns the first argument if it is null or undefined. Otherwise it returns the second.

<p id="demo"></p>

<script>
let name = null;
let text = "missing";
let result = name ?? text;
document.getElementById("demo").innerHTML = "The name is " + result; 
</script>

The name is missing

 

 

 

The Optional Chaining Operator (?.)

<p>Car name is:</p>
<p id="demo"></p>

<script>
const car = {type:"Fiat", model:"500", color:"white"};
let name = car?.name;
document.getElementById("demo").innerHTML = name;
</script>

Car name is:
undefined