Answers for "how to return falsy values js"

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 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.