@rbxts/jsnatives

isNaN

Determines whether the passed value is NaN (Not a Number).

Signature

function isNaN(value: number): boolean

Description

The Number.isNaN() method determines whether the passed value is the special NaN value. Unlike the global isNaN() function, it doesn't convert its argument to a number before testing.

Parameters

value: The value to be tested for being NaN.

Return value

true if the given value is NaN, otherwise false.

Examples

Basic Usage

// Testing for NaN
Number.isNaN(NaN);               // true
Number.isNaN(Number.NaN);        // true
Number.isNaN(0 / 0);             // true (result is NaN)

// Regular numbers
Number.isNaN(42);                // false
Number.isNaN(-42);               // false
Number.isNaN(0);                 // false
Number.isNaN(Infinity);          // false

// Non-numbers (where global isNaN would return true)
Number.isNaN("NaN");             // false (string, not a Number)
Number.isNaN(undefined);         // false
Number.isNaN({});                // false
Number.isNaN("blabla");          // false

Checking Calculation Results

// Check if a calculation produced a valid result
function safeCalculate(a: number, b: number): number | null {
  const result = a / b;

  if (Number.isNaN(result)) {
    return null; // Invalid result
  }

  return result;
}

// Usage
safeCalculate(10, 2);    // 5
safeCalculate(0, 0);     // null (0/0 is NaN)