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In my angular 2 application I have declared 2 object arrays.

users: User[];
selectedUsers: User[];

Now I am using the filter() method to return an array with objects whose checked property is true.

this.selectedUsers = this.users.filter(user => user.isChecked == true);

The problem is the references for elements of both arrays are same. So is there a way to that I can filter out objects and return array of new objects(new reference)?

In my angular 2 application I have declared 2 object arrays.

users: User[];
selectedUsers: User[];

Now I am using the filter() method to return an array with objects whose checked property is true.

this.selectedUsers = this.users.filter(user => user.isChecked == true);

The problem is the references for elements of both arrays are same. So is there a way to that I can filter out objects and return array of new objects(new reference)?

• javascript
• typescript

Share Improve this question Follow edited Jan 5, 2017 at 14:27 Poul Kruijt 72k1212 gold badges152152 silver badges151151 bronze badges asked Jan 5, 2017 at 14:21 kiranghule27kiranghule27 44311 gold badge88 silver badges2020 bronze badges 3

• So you want a new array with a clone of every user which is checked, right? – Pablo Lozano Commented Jan 5, 2017 at 14:24
• That won't work, since filter expects a function that returns a bool and doesn't care for the result. This should work: this.selectedUsers = this.users.filter(user => user.isChecked == true).map(user => deepCloneUser(user));. If writing deep clone is too tedious manually lodash & co have utility methods for it. – Matthias247 Commented Jan 5, 2017 at 14:29
• @Pablo yes. Basically creating new objects with same properties as the ones that are 'isChecked'. – kiranghule27 Commented Jan 5, 2017 at 16:53

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3 Answers 3

Sorted by: Reset to default 9

You can always use Array.prototype.map to create a new array and Object.assign to create a new object:

this.users.filter(user => user.isChecked).map(u => Object.assign({},u));

You can use _.cloneDeep function ("lodash" library):

for implement lodash in typescript you need:

npm i -S lodash

and the @types lib :

npm i -S @types/lodash

and in your code:

import * as _ from 'lodash'

let cloneCheckedObject = _.cloneDeep(this.users.filter(user => user.isChecked);

Lets take @Amir answer and make it a tiny bit more typescript friendly:

this.users.filter(user => user.isChecked).map(u => {...u});

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