Bring back typedef property expansion

[mjbvz]

From @zavr-1 on July 18, 2018 20:25

In the newer version, I can only see the type of an argument which is an object, compared to how it was expanded in the previous versions.

It was actually very useful to see all properties on hover which served as a documentation.

I think if you hide the details of the type, you should also provide means to expand its properties via a UI, or provide a setting for it.

Copied from original issue: microsoft/vscode#54609

[mjbvz]

@zavr-1 do you see the @param properties if you scroll the hover?

[mhegazy]

@mjbvz maybe we need a way for ppl to "expand" a type alias declaration in the quick info.. are there any experiences like that in VSCode that we can model after?

[mjbvz]

Yes, I think I misunderstood this specific issue but having a way to expand types dynamically in hover would be very helpful. We have no concept of this in VS Code currently. Visual Studio might though

[mhegazy]

VS does not either. i think eclipse does.

[zavr-1]

@mhegazy @mjbvz
I can achieve this expansion by writing

/** @type {DoneStatus} */
var ns = {
}

/**
 * @typedef {{ status: Status,  m(n: number): void }} DoneStatus
 * @typedef {{
  hello: 'world'
}} Status */

However, there is no way to provide a description of a property for auto-complete hints

Therefore, the quickest solution before providing expansion of types is to allow writing JSDoc where a type is specified both with {{ ... }} to allow for expanded properties in preview, and has @prop for description of properties in the auto-complete.

/**
 * @typedef {{ status: Status,  m(n: number): void }} DoneStatus
 * @prop {Status} status The status
 * @typedef {{
  hello: 'world'
}} Status */

(Note the additional @prop in the typedef).

[zavr-1]

@weswigham I don't think that your change from here which is the point of this topic will be reverted, but is it possible to at least implement the suggestion in the post above ^? thanks.

[weswigham]

@zavr-1 That PR brought JSDoc into the same style of printout that we used for TS, but the core issue is that when a type is aliased within quickinfo, there's no way to inspect what's "inside the alias" right at that point, as it were. Hence @mhegazy and @mjbvz 's remarks on new UI to enable that in vscode/VS. We've talked about it in the past - it seems generally useful for inspecting large type hierarchies.

[zavr-1]

@weswigham OK but why is it possible to inspect what's inside using

@typedef {{ prop: TypeB }} TypeA

but not

@typedef {Object} TypeA
@prop {TybeB} prop

What I'm saying OK fine I get the point of aliases for large type hierarchies, but could you not allow me to write {{ prop: TypeB }} AND define a property under @typedef so it's visible in the preview? Because then it's best of both worlds -- I can define a type to be shown as an alias only, or I can define it as expanded one. Currently, I can do these both things, but I can't describe a property for preview if I use {{ prop: TypeB }} notation.

At the moment, it's either:

Forcing nested properties, but no description in auto-complete

/**
 * @typedef {{ prop: TypeB }} TypeA
 * @prop {TypeB} prop A test Prop
 * @typedef {string} TypeB
 */

Type alias, with description in auto-complete

/**
 * @typedef {Object} TypeA
 * @prop {TypeB} prop A test Prop
 * @typedef {string} TypeB
 */