es-toolkit/dist/compat/predicate/isNil.js

A state-of-the-art, high-performance JavaScript utility library with a small bundle size and strong type annotations.

//#region src/compat/predicate/isNil.ts
/**
* Checks if a given value is null or undefined.
*
* This function tests whether the provided value is either `null` or `undefined`.
* It returns `true` if the value is `null` or `undefined`, and `false` otherwise.
*
* This function can also serve as a type predicate in TypeScript, narrowing the type of the argument to `null` or `undefined`.
*
* @param x - The value to test for null or undefined.
* @returns `true` if the value is null or undefined, `false` otherwise.
*
* @example
* const value1 = null;
* const value2 = undefined;
* const value3 = 42;
* const result1 = isNil(value1); // true
* const result2 = isNil(value2); // true
* const result3 = isNil(value3); // false
*/
function isNil(x) {
	return x == null;
}
//#endregion
exports.isNil = isNil;