javascript, what does object.assign do code example

Example 1: javascript assign

const obj = { a: 1 };
const copy = Object.assign({}, obj);
console.log(copy); // { a: 1 }

Example 2: javascript object.assign

const target = { a: 1, b: 2 };
const source = { b: 4, c: 5 };

const returnedTarget = Object.assign(target, source);

console.log(target);
// expected output: Object { a: 1, b: 4, c: 5 }

console.log(returnedTarget);
// expected output: Object { a: 1, b: 4, c: 5 }