revision:
The Object.assign() static method copies all enumerable own properties from one or more source objects to a target object. It returns the modified target object.
Object.assign(target, ...sources)
Parameters:
target : required. The target object — what to apply the sources' properties to, which is returned after it is modified.
source : the source object(s) — objects containing the properties you want to apply.
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 === target);
// Expected output: true
<div>
<p id="assign-1"></p>
<p id="assign-2"></p>
</div>
<script>
const obj = { a: 1 };
document.getElementById("assign-1").innerHTML = "object : " + JSON.stringify(obj);
const copy = Object.assign({}, obj);
console.log(copy); // { a: 1 }
document.getElementById("assign-2").innerHTML = "object copy: " + JSON.stringify(copy);
</script>
<div>
<p id="assign-3"></p>
<p id="assign-4"></p>
<p id="assign-5"></p>
<p id="assign-6"></p>
<p id="assign-7"></p>
</div>
<script>
const object1 = { a: 1, b: 2, c: 3 };
const object3= { g: 1, h: 2, i: 3 };
const object2 = Object.assign({c: 4, d: 5}, object1);
const object4 = Object.assign({g: 34, h: 25}, object3);
console.log(object2.c, object2.d);
console.log(object4.g, object4.h);
document.getElementById("assign-3").innerHTML = "object2.c: " + (object2.c);
document.getElementById("assign-4").innerHTML = "object2.d: " + (object2.d);
document.getElementById("assign-5").innerHTML = "object4.g: " + (object4.g);
document.getElementById("assign-6").innerHTML = "object4.h: " + (object4.h);
</script>