TypedStimulusController - some Typescript love :)

[ajaishankar]

Hi

Have been playing with Stimulus, and came up with this sample that can automatically type the values, targets, outlets...

Would there be any interest in including a full implementation of this as part of Stimulus or would it be more suited as a separate package?

type Statics<Values extends object> = {
    values?: Values
}

function TypedStimulusController<Values extends object>(statics: Statics<Values>) {
    return class extends StimulusController {
        static values = statics.values
        constructor(context: Context) {
            super(context)
        }
    } as unknown as {
        new (context: Context): StimulusController & TypedValues<Values>
    }
}

type TypedValues<Values extends object> = {
    [K in keyof Values as `${K & string}Value`]:
        Values[K] extends NumberConstructor ? number
        : Values[K] extends StringConstructor ? string
        : unknown
}

const values = {
    url: String,
    interval: Number
}

class LoaderController extends TypedStimulusController({ values }) {
    connect() {
        fetch(this.urlValue).then(/* … */)
    }
}

class Context {}

class StimulusController {
    constructor(context: Context) {}
}

This will let Typescript users avoid having to manually override the types

  declare urlValue: string
  declare readonly hasUrlValue: boolean

See similar issue here: #723

[Marcus Wyatt]

I took a look at this and made some improvements (support default values) but was unable to make it work as well for targets and outlets

[Bruno Prieto]

TypeScript has already been removed from Turbo and I would not be surprised if it is removed from Stimulus soon

[ajaishankar]

Removed as in...? Stimulus itself is written in Typescript.

[Bruno Prieto]

Yes, but it will probably switch to JavaScript soon, just like Turbo did a few weeks ago

[ajaishankar]

Got it.

Even if the implementation switches to Javascript (for whatever reason), the type definitions would be published.

Anyway what I proposed is a nicety for the end typescript users, and can definitely live outside Stimulus as a separate package.

[ajaishankar]

https://world.hey.com/dhh/turbo-8-is-dropping-typescript-70165c01

Ok, not part of Stimulus 😄