es-toolkit/dist/object/deepFreeze.js

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

//#region src/object/deepFreeze.ts
/**
* Deeply freezes an object, making it and all nested objects immutable.
*
* Unlike `Object.freeze`, which only freezes the immediate properties of an object,
* `deepFreeze` recursively freezes all nested objects and arrays.
*
* @template T - The type of the object.
* @param {T} obj - The object to deeply freeze.
* @returns {T} The deeply frozen object.
*
* @example
* const frozen = deepFreeze({ user: { name: "Alex", age: 20 } });
*
* frozen.user = {}; // TypeError in strict mode
* frozen.user.age = 22; // TypeError in strict mode
*/
function deepFreeze(obj) {
	if (obj === null || typeof obj !== "object") return obj;
	Object.freeze(obj);
	const keys = Object.keys(obj);
	for (let i = 0; i < keys.length; i++) {
		const value = obj[keys[i]];
		if (value !== null && typeof value === "object" && !Object.isFrozen(value)) deepFreeze(value);
	}
	return obj;
}
//#endregion
exports.deepFreeze = deepFreeze;