Angular.copy support for ES6 Map (and other ES6 types?)

[phasmal]

I'm submitting a ...

• bug report
• feature request
• other (Please do not submit support requests here (see above))

Current behavior:
angular.copy when called on an object containing an ES6 Map object fails to copy the Map contents. This is surprising for the developer-user since they would expect the new object to contain all the attributes of the old one, including contents (angular.copy advertises as a deep copy)

Expected / new behavior:

Addition of ES6 Map copy would mean angular.copy behaves as expected regardless of the presence of a Map in an object.

I haven't looked at other ES6 types, but I would expect angular.copy should sensibly copy them as well, if it doesn't already.

Minimal reproduction of the problem with instructions:

> m = new Map()
Map(0) {}

> m.set('a', 'b')
Map(1) {"a" => "b"}

> o = {myProperty : m}
Object {myProperty: Map(1)}

> c = angular.copy(o)
Object {myProperty: Map}

> o.myProperty
Map(1) {"a" => "b"}

> c.m
Map {}

Angular version: 1.x.y

1.6.4-local+sha.617b36117

looking at latest code, it is iterating keys, which won't work for maps:
https://github.com/angular/angular.js/blob/master/src/Angular.js#L902

> m = new Map()
Map(0) {}

> m.set('a', 'b')
Map(1) {"a" => "b"}

> for (k in m) { console.log(k)}
undefined

Browser: [all | Chrome XX | Firefox XX | Edge XX | IE XX | Safari XX | Mobile Chrome XX | Android X.X Web Browser | iOS XX Safari | iOS XX UIWebView | iOS XX WKWebView ]

Chrome 59.0.3071.86 (Official Build) (64-bit)

Tried replicating on Firefox, but was an older version of angular and caused error:

> m = new Map()
Map {  }

> m.set('a', 'b')
Map { a: "b" }

> c = angular.copy(m)
TypeError: Map.prototype.forEach called on incompatible object

> angular.version
Object { full: "1.3.20", major: 1, minor: 3, dot: 20, codeName: "shallow-translucence" }

Looking at code, though it wouldn't work for Map on any browser that doesn't allow key iteration over map values (every browser I suspect).

For example, on FF:

> for (k in m) { console.log(k)}
undefined

Anything else:

This overlaps with the following issue:
#10304

However, that issue is talking about general 'iterable' object support (of which ES6 collections are a sub-set) which is a more intractable problem. This is focused specifically on ES6 collections.

Suggest treating Map similar to Array as a special case and using the built-in iteration features to populate the copy.

Alternately, define a global javascript 'clone' standard that objects can declare support for and make angular.copy redundant ;)

[frederikprijck]

There's an open (but stale) PR regarding this:
#15697

[phasmal]

Adding a list of unsupported types doesn't change this feature request. I'm still requesting that copy supports Map/other ES6 types rather than not supporting them.

[phasmal]

... unless this is saying 'won't fix this' separate from the fact that it's been commented that they're not supported?

Otherwise, can we have this reopened? or should I copy/paste the description into a new request?

[frederikprijck]

I'd guess it's due to the fact that AngularJS is currently in LTS that features like this aren't getting added.

[petebacondarwin]

@phasmal - indeed @frederikprijck is correct. We are now well into the LTS period and we are not adding new features to AngularJS.

[phasmal]

Ahh, great, thanks for the clarification - that makes much more sense!