Object Manipulation

Merging

• Object.assign

  • mutates left-hand-side
  • since ES5
  • iterates enumerable own properties

• ...

  • creates new object
  • since ES9
  • iterates enumerable own properties

let original = { a: 1, b: 2 };

// mutates original
let objectClone = Object.assign(original, { foo: 'foo' }); 

// or create new object
let objectClone = Object.assign({}, original, { foo: 'foo' });

// spread operator always create new object
let objectClone = { ...object };