angular2: how to copy object into another object

Please help me in order to copy the object into another object using angular 2?

In angular, I used angular.copy() to copy objects to the loose reference of the old objects. But, when I used the same in angular 2 getting below error:

>Error: angular is not defined.

Solution

Angular2 developed on the ground of modern technologies like TypeScript and ES6.

So you can just do let copy = Object.assign({}, myObject).

Object assign - nice examples.

For nested objects : let copy = JSON.parse(JSON.stringify(myObject))

let copy = Object.assign({}, myObject).  as mentioned above

but this wont work for nested objects. So an alternative would be

let copy =JSON.parse(JSON.stringify(myObject))

As suggested before, the clean way of deep copying objects having nested objects inside is by using lodash's cloneDeep method.

For Angular, you can do it like this:

Install lodash with yarn add lodash or npm install lodash.

In your component, import cloneDeep and use it:

import * as cloneDeep from 'lodash/cloneDeep';
...
clonedObject = cloneDeep(originalObject);

It's only 18kb added to your build, well worth for the benefits.

I've also written an article here, if you need more insight on why using lodash's cloneDeep.

You can do in this in Angular with ECMAScript6 by using the spread operator:

let copy = {...myObject};

let course = {
  name: 'Angular',
};

let newCourse= Object.assign({}, course);

newCourse.name= 'React';

console.log(course.name); // writes Angular
console.log(newCourse.name); // writes React

For Nested Object we can use of 3rd party libraries, for deep copying objects. In case of lodash, use _.cloneDeep()

let newCourse= _.cloneDeep(course);

Try this.

Copy an Array :

const myCopiedArray  = Object.assign([], myArray);

Copy an object :

const myCopiedObject = Object.assign({}, myObject);

Loadsh is the universal standard library for coping any object deepcopy. It's a recursive algorithm. It's check everything and does copy for the given object. Writing this kind of algorithm will take longer time. It's better to leverage the same.

Object.assign will only work in single level of object reference.

To do a copy in any depth use as below:

let x = {'a':'a','b':{'c':'c'}};
let y = JSON.parse(JSON.stringify(x));

If want to use any library instead then go with the loadash.js library.

thank you Saif from above. I tried his suggestion and it worked like a charm after I tried for three days to get my code to work.

  this.sElectionFinal.subscribe((election) => {
 const electionCopy = Object.assign({},election)
  this.electionsFinal.push(electionCopy)})