Object.assign(source, target) code example

Example 1: object assign

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

Example 2: copy an object with object.assign

// We want to update status property value to 'online'
const data = {
  user: 'CamperBot',
  status: 'offline',
  friends: '732,982',
};

// Object.assign takes in a target object (1st parameter) and source objects 
// (rest of the parameter list). Source object properties are mapped to the 
// target object (which is usually empty). Any matching properties are 
// overwritten by the source objects
const newObject = Object.assign({}, data, {status: 'online'})

console.log(newObject)
/* 
  {
    user: 'CamperBot',
    status: 'online',
    friends: '732,982',
  }
*/