JAVASCRIPT

javascript falsy values

the number 0
the BigInt 0n
the keyword null
the keyword undefined
the boolean false
the number NaN
the empty string "" (equivalent to '' or ``)

falsy values javascript

// JS Essentials: Falsy Values

false
undefined
null
NaN
0 or +0 or -0
"" or '' or `` (empty string)

// Everything else is truthy

falsy value javascript

//false,0,"",undefined,NaN are falsy value and all other value are truthy in js

javascript falsy values

undefined
null
NaN
0
"" (empty string)
false

falsy values javascript

false		//The keyword false.
0			//The Number zero (so, also 0.0, etc., and 0x0).
-0			//The Number negative zero (so, also -0.0, etc., and -0x0).
0n, -0n		//The BigInt zero and negative zero (so, also 0x0n/-0x0n).
"", '', ``	//Empty string value.
null		//the absence of any value.
undefined	//the primitive value.
NaN			//not a number.

document.all	
//Objects are falsy if and only if they have the [[IsHTMLDDA]] internal slot.
//That slot only exists in document.all and cannot be set using JavaScript.

falsy values in js

// falsy values in javascript

1) false
2) 0, -0, 0n
3) null
4) undefined
5) NaN
6) "", '', `` // empty string

javascript falsy values

if (true)
if ({})
if ([])
if (42)
if ("0")
if ("false")
if (new Date())
if (-42)
if (12n)
if (3.14)
if (-3.14)
if (Infinity)
if (-Infinity)

js falsy values

    let a = false
    let b = 0
    let c = -0
    let d = 0n
    let e = ''
    let f = null
    let g = undefined
    let h = NaN

falsy values javascript

//check falsy value using Boolean()
//if it falsy it return false

let falsyValue = [0, "", NaN, undefined, false, null, -0, 022, 100, {}, []]

falsyValue.forEach(ele => {
    console.log(Boolean(ele))
})

falsy value in JavaScript

if (false)
if (null)
if (undefined)
if (0)
if (-0)
if (0n)
if (NaN)
if ("")

Falsy value in javascript

false
0
- 0
""
null
undefined
NaN