AngularJS : copy vs extend

Question

Explanation :

we come across some situation in which we need to copy one object to another object. In that case, we probably have two solutions: ang

Answer 1

For the copy of the object the following things metters.

• Object points to same memory location or not

  • Normal copy - Yes
  • Angular copy - No
  • Angular extend - No
  • Angular merge - No

• Inner object points to the same memory location or not

  • Normal copy - Yes
  • Angular copy - No
  • Angular extend - No
  • Angular merge - No

• Does copy keep the current child objects or remove that objects

  • Normal copy - Override
  • Angular copy - Override
  • Angular extend - Keep
  • Angular merge - Keep

Here is the plunker copy for that

// '=' assignment copy
console.info('assignment copy');
var mySource = {'name' : 'sakshi', 'age' : '24', 'obj' :{'key':'value'}}
var myDest = {oldObj:'old'} //old properties will be override
myDest = mySource;
mySource.name = "Rohit";
console.log(mySource); // Object {name: "Rohit", age: "24", obj: Object}
console.log(myDest); // Object {name: "sakshi", age: "24", obj: Object}
console.log(mySource === myDest); // true         //points to same object
console.log(mySource.obj === myDest.obj); // true //points to same object


// angular.copy()
console.info('angular copy');
var mySource = {'name' : 'sakshi', 'age' : '24', 'obj' :{'key':'value'}}
var myDest = {oldObj:'old'} //old properties will be override
angular.copy(mySource,myDest);
mySource.name = "Rohit";
console.log(mySource); // Object {name: "Rohit", age: "24", obj: Object}
console.log(myDest); // Object {name: "sakshi", age: "24", obj: Object}
console.log(mySource === myDest); // false //points to different object
console.log(mySource.obj === myDest.obj); // false //points to different object

// angular.extend()
console.info('angular extend');
var mySource = {'name' : 'sakshi', 'age' : '24', 'obj' :{'key':'value'}}
var myDest = {oldObj:'old'}
angular.extend(myDest,mySource);
mySource.name = "Rohit";
console.log(mySource); // Object {name: "Rohit", age: "24", obj: Object}
console.log(myDest); // Object {oldObj:'old',name: "sakshi", age: "24", obj: Object}
mySource.obj.key = '123';
console.log(myDest.obj.key);
console.log(mySource === myDest); // false //points to different object
console.log(mySource.obj === myDest.obj); // True //points to same object

// angular.extend()
console.info('angular merge');
var mySource = {'name' : 'sakshi', 'age' : '24', 'obj' :{'key':'value'}}
var myDest = {oldObj:'old'}
angular.merge(myDest,mySource);
mySource.name = "Rohit";
console.log(mySource); // Object {name: "Rohit", age: "24", obj: Object}
console.log(myDest); // Object {oldObj:'old',name: "sakshi", age: "24", obj: Object}
console.log(mySource === myDest); // false //points to different object
console.log(mySource.obj === myDest.obj); // false //points to different object