Merge two objects recursively

[satazor]

At the moment we have mixIn that merges two objects but not recursively.
We could have something similar to mootools Object.merge

[JamesMGreene]

+1

[millermedeiros]

this is indeed useful and not hard to implement. +1

[millermedeiros]

one thing I realized while coding it is that since objects are passed by reference they will end up being updated/edited during the merge, so the proper way of implementing it to avoid undesired side-effects is to clone the object before merging...

what do you guys think? should it also clone arrays?

Current behavior:

var obj1 = {a: 1, b : { c: 1}};
var obj2 = {a: 2, b : { c : { d : 2 } }};
var obj3 = { b : { e : 3 } };

merge(obj1, obj2, obj3); // { a: 2, b : { c : { d : 2 }, e : 3 } }

// since objects are passed by reference this weird behavior happens
// obj2 is also affected during merge
obj1.b === obj2.b; // true
obj2.b.e === 3;    // true

PS: I didn't merged this into master yet since current behavior is funky

[JamesMGreene]

Yes, I would say both objects and arrays should be cloned. Some people would then say, "what about object/class instances?"; I, however, have never found myself wanting to merge any structure that contains such things... only plain data objects.

[JamesMGreene]

Also, you may find some of the discussion interesting in this JSFixed thread: https://github.com/JSFixed/JSFixed/issues/16

[satazor]

bump!

[millermedeiros]

@satazor thanks for the "bump!", I've been busy lately and forgot about it. Merged into master.

[JamesMGreene]

@millermedeiros Is the committed behavior still funky?

[millermedeiros]

@JamesMGreene now it clones all the Object/Array/Date/RegExp, so it shouldn't cause any side-effects. see specs for more info

[JamesMGreene]

Greats, thanks!

[satazor]

@millermedeiros no problem! I was long waiting for this function :D