es-toolkit/dist/predicate/isUndefined.js

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

//#region src/predicate/isUndefined.ts
/**
* Checks if the given value is undefined.
*
* This function tests whether the provided value is strictly equal to `undefined`.
* It returns `true` if the value is `undefined`, and `false` otherwise.
*
* This function can also serve as a type predicate in TypeScript, narrowing the type of the argument to `undefined`.
*
* @param x - The value to test if it is undefined.
* @returns true if the value is undefined, false otherwise.
*
* @example
* const value1 = undefined;
* const value2 = null;
* const value3 = 42;
*
* console.log(isUndefined(value1)); // true
* console.log(isUndefined(value2)); // false
* console.log(isUndefined(value3)); // false
*/
function isUndefined(x) {
	return x === void 0;
}
//#endregion
exports.isUndefined = isUndefined;