1351635 - Returns ES6 class information in Grip

Status: RESOLVED FIXED

(DevTools :: Console, enhancement, P3)

Description

[Nicolas Chevobbe [:nchevobbe]]

At the moment, there's no way to tell if a Grip represent an ES6 class [1].
The grip labels it as a function, which, even if correct, does not convey much meanings for the users (and could be misleading since you can't call it without the `new` keyword).

It would be nice if we could return in the grip if we are dealing with a class, and maybe what class it extends.

I'm not sure but it looks like the changes we'd have to do can happen in this function  : http://searchfox.org/mozilla-central/source/devtools/server/actors/object.js#1117-1155


[1] Grip example : 
```
{
  "from": "server2.conn5.child1/consoleActor2",
  "input": "(class A{})",
  "result": {
    "type": "object",
    "actor": "server2.conn5.child1/obj32",
    "class": "Function",
    "extensible": true,
    "frozen": false,
    "sealed": false,
    "name": "A",
    "displayName": "A"
  },
  "timestamp": 1490770293758,
  "exception": null,
  "frame": null,
  "helperResult": null,
  "notes": null
}
```

Comment 1

[Nicolas Chevobbe [:nchevobbe]]

Thinking about this a little more, I think we could even have all the method, and if they are static or not so we can do a better job at representing classes.

We could do the same thing that we do for plain object, which is having a `preview` property that exposes those additional information.
This could looks like: 

```
{
  "from": "server2.conn2.child1/consoleActor2",
  "input": "(A  = {constructor() {}, eat(){}})",
  "result": {
    "type": "object",
    "actor": "server2.conn5.child1/obj32",
    "class": "Function",
    "extensible": true,
    "frozen": false,
    "sealed": false,
    "name": "A",
    "displayName": "A"
    "preview": {
      "kind": "Class",
      "extends" : {/* extended class or null */},
      "methods": {
        "constructor": {
          "configurable": true,
          "enumerable": true,
          "writable": true,
          "value": {
            "type": "object",
            "actor": "server2.conn2.child1/obj38",
            "class": "Function",
            "extensible": true,
            "frozen": false,
            "sealed": false,
            "name": "constructor",
            "displayName": "constructor",
            "location": {
              "url": "debugger eval code",
              "line": 1
            }
          }
        },
        "eat": {
          "configurable": true,
          "enumerable": true,
          "writable": true,
          "value": {
            "type": "object",
            "actor": "server2.conn2.child1/obj39",
            "class": "Function",
            "extensible": true,
            "frozen": false,
            "sealed": false,
            "name": "eat",
            "displayName": "eat",
            "location": {
              "url": "debugger eval code",
              "line": 1
            }
          }
        }
      }
    }
  },
  "timestamp": 1490788386282,
  "exception": null,
  "frame": null,
  "helperResult": null
}
```

Comment 2

[Nicolas Chevobbe [:nchevobbe]]

Attachment: Bug 1351635 - Return isClassConstructor in class grip. r=loganfsmyth.

A test is added to ensure isClassConstructor has the expected
value for ES6 class grips.

Depends on D50935

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e54a4d3a92b8
Return isClassConstructor in class grip. r=loganfsmyth.

Comment 4

[Cristina Coroiu [:ccoroiu]]

https://hg.mozilla.org/mozilla-central/rev/e54a4d3a92b8

Comment 5

[Arthur Iakab [arthur_iakab]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/e54a4d3a92b8