@rbxts/jsnatives

Object.assign

Copies all enumerable own properties from one or more source objects to a target object.

Signature

function assign<T, U>(target: T, ...sources: U[]): T & ReduceObjectArray<U>

Description

The Object.assign() method copies all enumerable own properties from one or more source objects to a target object. It returns the modified target object.

Properties in the target object will be overwritten by properties in the sources if they have the same key. Later sources' properties will similarly overwrite earlier ones.

Examples

Merging objects

const target = {a: 1};
const sourceArray = [1, 2, 3];
const sourceSet = new Set([1, 2, 3]);
const sourceMap = new Map([["a", 8], ["b", 2], ["c", 3]]);

const result = Object.assign(target, sourceArray, sourceSet, sourceMap);
print(result); // {a: 8, 0: 1, 1: true, 2: true, 3: true, b: 2, c: 3}

Working with proxies

const objA = {c: 1}

const target = {}

const proxiedTarget = new Proxy(target, {
  set: (target, prop, value) => {
    target[prop] = value;
    return true;
  }
})

const proxiedSource = new Proxy({}, {
  get: (target, prop) => {
    return prop === "a" ? 2 : prop;
  },
  ownKeys: () => ["a", "b"]
})

// Note that a proxy is technically an empty object
const result = Object.assign(proxiedTarget, proxiedSource, objA);
print(result, target, JSON.stringify(proxiedTarget));
// {} {a: 2, b: 2, c: 1}, {"a":2,"b":2,"c":1}