angularjs - extend recursive

Question

I would like to extend some properties recursive (aka. deep copy). much like jQuery does. I'm not including jquery only b/c of one thing.

jQuery.extend( true, target, object1 )

is there any elegant way you know of that does it with simple javascript or angularjs?

update please take a look and try to accomplish the same result http://plnkr.co/edit/GHabYbyhsqtfBPtplksO?p=preview

i did look into .copy() but the "properties (for objects) are deleted"

But you could simply copy $.extend from jQuery's source? It's not that hard to find, and pretty stand-alone. — Bergi
– Bergi, Commented Dec 17, 2014 at 20:54

Michael Herold · Accepted Answer · 2014-08-19 18:10:41Z

28

Here is an extendDeep function based off of the angular.extend function. If you add this to your $scope, you would then be able to call

$scope.meta = $scope.extendDeep(ajaxResponse1.myMeta, ajaxResponse2.defaultMeta);

and get the answer you are looking for.

$scope.extendDeep = function extendDeep(dst) {
  angular.forEach(arguments, function(obj) {
    if (obj !== dst) {
      angular.forEach(obj, function(value, key) {
        if (dst[key] && dst[key].constructor && dst[key].constructor === Object) {
          extendDeep(dst[key], value);
        } else {
          dst[key] = value;
        }     
      });   
    }
  });
  return dst;
};

Note: This function has the side-effect of copying values from later arguments into the earlier arguments. For a simple fix to this side effect, you can change dst[key] = value to dst[key] = angular.copy(value).

edited Aug 19, 2014 at 18:10

Michael Herold

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answered Mar 9, 2013 at 14:34

Ryan O'Neill

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7 Comments

Endless Over a year ago

That's also a good solution, wich angular team had done something like a first param boolen (like jquery)

Ryan O'Neill Over a year ago

Agreed. I would too, just wanted to demonstrate an easy way to do it using angular's methods.

Bennett McElwee Over a year ago

I think the if (dst[key]) should actually be if (dst[key] && dst[key].constructor && dst[key].constructor === Object) - it deosn't seem to work correctly otherwise

Richard Morgan Over a year ago

This is the better answer since it supports multiple arguments, but would you please incorporate the fix in @BennettMcElwee's comment?

Godders Over a year ago

What is the purpose of the check for dst[key].constructor === Object? Would a simple if (dst[key] && angular.isObject(dst[key])) work?

|

Julien P · Accepted Answer · 2016-04-13 16:08:16Z

17

All the answers here are valid for versions of Angular before 1.4

As of Angular 1.4, you can use angular.merge to do exactly that:

Unlike extend(), merge() recursively descends into object properties of source objects, performing a deep copy.

https://docs.angularjs.org/api/ng/function/angular.merge

edited Apr 13, 2016 at 16:08

answered Mar 19, 2015 at 14:53

Julien P

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1 Comment

Cédric Françoys Over a year ago

deprecated since 1.6.5 : docs.angularjs.org/api/ng/function/angular.merge

Stewie · Accepted Answer · 2013-03-09 14:29:36Z

7

function deepExtend(destination, source) {
  for (var property in source) {
    if (source[property] && source[property].constructor &&
     source[property].constructor === Object) {
      destination[property] = destination[property] || {};
      arguments.callee(destination[property], source[property]);
    } else {
      destination[property] = source[property];
    }
  }
  return destination;
}

Plunker

Src: https://gist.github.com/gregdangelo/2343158

answered Mar 9, 2013 at 14:29

Stewie

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2 Comments

Richard Morgan Over a year ago

This answer only supports 2 arguments. The one by Ryan supports multiple arguments like jQuery.extend does, but be sure to use Bennett MeElwee's suggestion.

chrismarx Over a year ago

arguments.callee usage is discouraged now -developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…

ses · Accepted Answer · 2014-12-22 19:20:15Z

1

Building on Ryan's code, you can shorten the object check and you should also NOT extend functions so you don't override object pointers.

var extendDeep = function extendDeep(dst) {
    angular.forEach(arguments, function(obj) {
        if (obj !== dst) {
            angular.forEach(obj, function(value, key) {
                if (dst[key] && angular.isObject(dst[key])) {
                    extendDeep(dst[key], value);
                } else if(!angular.isFunction(dst[key])) {
                    dst[key] = value;
                }
            });
        }
    });
    return dst;
};

edited Dec 22, 2014 at 19:20

ses

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answered Nov 10, 2014 at 15:47

amcdnl

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Comments

Steve Giraud · Accepted Answer · 2014-12-31 09:33:36Z

0

The same solution as Ryan but with support for array merge

function extendDeep(dst) {
      angular.forEach(arguments, function (obj) {
          if (obj !== dst) {
            angular.forEach(obj, function (value, key) {
                if (dst[key] && dst[key].constructor && dst[key].constructor === Object) {
                  extendDeep(dst[key], value);
                } else if (dst[key] && dst[key].constructor && dst[key].constructor === Array) {
                  dst[key].concat(value);
                } else if(!angular.isFunction(dst[key])) {
                  dst[key] = value;
                }
              }
            );
          }
        }
      );
      return dst;
    }

answered Dec 31, 2014 at 9:33

Steve Giraud

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Comments

charlietfl · Accepted Answer · 2013-03-09 13:05:39Z

-1

Angular has a copy method:

angular.copy

answered Mar 9, 2013 at 13:05

charlietfl

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3 Comments

Jamie Pate Over a year ago

This solution deletes the contents of the destination. angular.copy is used for a different reason than angular.extend

user400654 Over a year ago

Definitely not the correct answer for this question, but... this answer helped point me in the right direction for my particular case. :)

neaumusic Over a year ago

I'm thinking the OP meant angular.extend(myDeepCopy, angular.copy(originalObject))

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