JS: Number.isNaN

By Xah Lee. Date: . Last updated: .

Number.isNaN ( number )

If number is NaN, return true, else false.

(NaN is a primitive value of number type that represents “not a number”.)

[see JS: NaN]

console.log ( Number.isNaN ( NaN ) ); // true

console.log ( Number.isNaN ( "NaN" ) ); // false
console.log ( Number.isNaN ( "3" ) ); // false
console.log ( Number.isNaN ( 3 ) ); // false
console.log ( Number.isNaN ( Infinity ) ); // false

Number.isNaN and the global isNaN are different.

isNaN converts argument to number first. Number.isNaN does not.

[see JS: isNaN]

JS Number

  1. Format Number
  2. String to Number
  3. Random Number

JS String

  1. String Overview
  2. Template String
  3. Char, Code Unit, Codepoint
  4. String Escape Sequence
  5. Unicode Escape Sequence

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