Props with Vue3 and Typescript

[Lalaluka]

Hi, I had a go on migrating some of our Vue2 Microfrontends to Vue3. Also, I threw Typescript into the mix.

I'm not sure if it's an issue with the Package itself or just a missing bit of the documentation.

I encountered a problem with the usage of props. The SingleSpaOptsVue3 type doesn't have the props defined to typescript won't compile it. This is of course Typescript exclusive

const vueLifecycles = singleSpaVue({
  createApp,
  appOptions: {
    render() {
      return h(App, {
        // single-spa props are available on the "this" object. Forward them to your component as needed.
        // https://single-spa.js.org/docs/building-applications#lifecyle-props
        // if you uncomment these, remember to add matching prop definitions for them in your App.vue file.
        /*
        name: this.name,
        mountParcel: this.mountParcel,
        */
        singleSpa: this.singleSpa,
        //Property 'singleSpa' does not exist on type 'AppOptions | ((opts: SingleSpaOptsVue2 | SingleSpaOptsVue3, props: object) => Promise<AppOptions>)'.
        //Property 'singleSpa' does not exist on type '(opts: SingleSpaOptsVue2 | SingleSpaOptsVue3, props: object) => Promise<AppOptions>'.ts(2339)
      });
    },
  },
});

It can easily be fixed with an this alis (which is kind of ugly and talint doesn't like):

const vueLifecycles = singleSpaVue({
  createApp,
  appOptions: {
    render() {
      const thisalias: any = this;
      return h(App, {
        // single-spa props are available on the "this" object. Forward them to your component as needed.
        // https://single-spa.js.org/docs/building-applications#lifecyle-props
        // if you uncomment these, remember to add matching prop definitions for them in your App.vue file.
        /*
        name: this.name,
        mountParcel: this.mountParcel,
        */
        singleSpa: thisalias.singleSpa,
      });
    },
  },
});

Using appOptions as an async function works of course (with some types on the props).

const vueLifecycles = singleSpaVue({
  createApp,
  async appOptions(props: any) {
    return {
      render: h(App, {
        singleSpa: props.singleSpa,
      })
    }
  },
});

Maybe this should be described a bit better in the Docs? Or also improved in the generation? The example Comment suggesting to uncomment the Props is a bit wrong if Typescript is in place.

[joeldenning]

This sounds like the typescript definitions need to be updated. Here's the file where they can be updated:

https://github.com/single-spa/single-spa-vue/blob/main/types/single-spa-vue.d.ts

The single-spa library has the default props defined at https://github.com/single-spa/single-spa/blob/f67d6fcd404597a246636e302f1d9e7b0f8cd9c6/typings/single-spa.d.ts#L12 - those should be imported into single-spa-vue's types and then used so that this has those props on them.

Do you have interest in contributing a pull request with the fix?

[Lalaluka]

Yea im interested and will take a closer look the next few days.

Thanks for the initial ressources they look pretty helpfull!

[Lalaluka]

HI @joeldenning sorry for the late response.

I think the props are already handled in https://github.com/single-spa/single-spa-vue/blob/36aa8bbee13da5e47807da7c773b533f4df31377/types/single-spa-vue.d.ts#L6-L10 by the [key: string]: any; of course you could add the single-spa specific props there too (if wanted I have a PR ready).

But the real issue is the Union in line 15 onwards. https://github.com/single-spa/single-spa-vue/blob/36aa8bbee13da5e47807da7c773b533f4df31377/types/single-spa-vue.d.ts#L13-L19 This leads understandably to the errors. Tbh I would recommend updating https://github.com/single-spa/vue-cli-plugin-single-spa/blob/18e92aa559b489128edda8a5675f839e8022a267/template/src/main-vue-3.js#L12-L19 for Typescript configs updating the occurrences of this (from line 16-18) with a typecast like this: (<AppOptions>this).singleSpa.

I don't know if this is the preferred way. If yes I would be happy to contribute these changes.

tldr. Proposed Changes:

• [ ] Add SingleSpa specific Props to single-spa-vue
• [ ] Add typescript only typecast to vue3 Template

[joeldenning]

I think the best solution would be to type the render function properly. Typecasting with (<AppOptions>this) is a workaround, but the full solution is to change the function signature.

The first thing to try would be to add the render function along with the this type to single-spa-vue:

https://github.com/single-spa/single-spa-vue/blob/36aa8bbee13da5e47807da7c773b533f4df31377/types/single-spa-vue.d.ts#L6-L10

+ import { AppProps } from 'single-spa';
+
  type AppOptions = {
    el?: string | HTMLElement;
    data?: any;
+   render: (this: AppProps) => any;
    [key: string]: any;
  };

Since this is caller-dependent, I'm not sure if that will work. If not, you could make a similar change to vue-cli-plugin-single-spa. The this should be AppProps, not AppOptions, since it's the single-spa props that are put on the this, not the options.

[kosmos]

I have exactly the same issue. :(