CODEWITHSUNDEEP
javascriptangularjs
Eliseo D'Annunzio
Eliseo D'Annunzio

Reputation: 592

Angular.copy function

I noticed the following code recently in an Angular tutorial...

<div ng-app="myApp" ng-controller="formCtrl">
  <form novalidate>
    First Name:<br>
    <input type="text" ng-model="user.firstName"><br>
    Last Name:<br>
    <input type="text" ng-model="user.lastName">
    <br><br>
    <button ng-click="reset()">RESET</button>
  </form>
  <p>form = {{user}}</p>
  <p>master = {{master}}</p>
</div>

<script>
var app = angular.module('myApp', []);
app.controller('formCtrl', function($scope) {
    $scope.master = {firstName: "John", lastName: "Doe"};
    $scope.reset = function() {
        $scope.user = angular.copy($scope.master);
    };
    $scope.reset();
});
</script>

With respect to the line: $scope.user = angular.copy($scope.master);, could this not have been simplified to: $scope.user = $scope.master; seeing that $scope.master is going to be an immutable constant in this case?

Upvotes: 0

Views: 630

Answers (1)

Daniel A. White
Daniel A. White

Reputation: 190941

When you do = in JavaScript with objects, you are only assigning the reference, not creating a new object (new reference). angular.copy creates a new object in this case.

In code terms:

var obj1 = {}, var obj2 = {}
obj1 !== obj2; // true
obj1 = obj2;
obj1 === obj2; // true
obj1 = angular.clone(obj2);
obj1 !== obj2; // true

Upvotes: 3

Related Questions