In JS, this in object literals is untyped

[waderyan]

From @ishuvalov on September 20, 2016 7:54

• VSCode Version: Code 1.5.2 (66f37fd2a99eb9d628dd374d81d78835b410c39b, 2016-09-12T13:05:12.065Z)
• OS Version: Darwin x64 15.6.0

Steps to Reproduce:

1. Consider the following code:

(function(undefined) {
    MyView = Backbone.View.extend({
        secondFunc: function () {
            return;
        },

        mainFunc: function() {
            this.secondFunc()
        }
    });
})();

1. The Goto Definition, Peek Definition and other IntelliSense features are not working for this.secondFunc() call.

Copied from original issue: microsoft/vscode#12306

[waderyan]

From @joaomoreno on September 20, 2016 8:17

@ishuvalov This is going to be very hard to get from the language service, because this isn't really bound to anything by semantically analysing the code. It's only due to the implicit knowledge of how Backbone.View.extend works.

You could try using TypeScript, you'd get those language features all the way.

[waderyan]

From @ishuvalov on September 20, 2016 8:38

@joaomoreno Thank you for your comment! Let's omit Backbone

(function(undefined) {
    var myObj = {
        secondFunc: function () {
            return;
        },

        mainFunc: function() {
            this.secondFunc()
        }
    };
})();

Still not working. I understand the difficulties of this context, but the feature could work just finding all symbolic definitions in the workspace (or even just a current file) and allowing user to choose from. This how Sublime Text 3 works.
Unfortunately the TypeScript is not an option for my project.

[waderyan]

@ishuvalov thank you for opening this issue. I have repo'd this with JavaScript language service 2.0.2.

Sending this to the TypeScript team as they provide the JavaScript language service.

[mhegazy]

One option, in a .js file we can make the type of this to be the type of the containing object literal if no other better option is available.

[sandersn]

Basically, #8382, but only for JavaScript files, right? I think that could work.

[mhegazy]

i guess so.

[sandersn]

The second repro is fixed (and has been for some time) and the first can be fixed by improving backbone's types.