fix(docs): extend vue 2 info regarding types #750

rchl · 2021-11-30T21:57:57Z

I know this puts the instructions upside-down since you've been suggesting to remove Vue.extend while I've changed it to recommend Vue.extend. The rationale is that, based on testing and as stated in the comments in #741, Vue.extend is really the way to go to fix the inevitable type issues in Vue 2 projects and I haven't really found any downsides to it.

If you have any specific examples where Vue.extend would makes things worse type-wise then I can tweak the wording or change it completely.

Note that when working with Vetur, I'm used to having to help the type system in many situations by adding manual JSDoc comments (when using JS) so I would expect this to be the case with Volar also. But that shouldn't change the fact that Vue.extend is required in the first place.

Related #741

johnsoncodehk · 2021-12-01T07:37:21Z

If you don't care about the component props / events type-check and auto-complete in template, Vue.extend is fine. Otherwise you need to migrate to defineComponent from @vue/composition-api to support these features.

Could you mention this?

rchl · 2021-12-01T08:17:44Z

If you don't care about the component props / events type-check and auto-complete in template,

I'm trying to say that this already works. Check the simple https://github.com/rchl/volar-vue2-test project for example.

I know that using Composition API works better in terms of type support but I just can't understand why do you keep saying that Vue.extend breaks auto-complete in the template. This is simply not true. I'd need you to explain this clearly before I adjust the text.

EDIT: I've also added a simple method which requires annotation since the argument can't be inferred automatically.

johnsoncodehk · 2021-12-03T18:22:16Z

Sorry for not making it clear, I am talking about cross-component props auto-complete and type-checking.

It should have auto-complete for :test.

It should have type error for :test.

rchl · 2021-12-03T18:37:45Z

But that's not related to whether someone is using Vue.extend or not. It doesn't work even when not using Vue.extend on both index.vue and Tutorial.vue.
EDIT: edited as my initial comment wasn't entirely correct.

johnsoncodehk · 2021-12-03T18:58:54Z

Without Vue.extend it should works. But actually I planned to abandon support for cross-component props type-checking with export default { ... }, so I hope remove mentioned export default { ... } in this pr.

So user only have 3 option in future:

export default Vue.extend({ ... }): support type-check to <script> and <template>, but not support cross-component type-check.
export default defineComponent({ ... }): support type-check to <script> and <template> and cross-component
class component: support type-check to <script> and <template> and cross-component with additional code. (Methods not found when using mapGetters #21)

rchl · 2021-12-03T19:29:05Z

Seems to be working with Vue.extend also. (I've pushed this change to the repo so you can try yourself)

So to conclude:

cross-component props type-checking seems to be working with both Vue.extend and without
Type-checking within the component requires Vue.extend to work properly.

With that said, is there anything you want me to change in this PR?

johnsoncodehk · 2021-12-03T19:31:50Z

@rchl emmmm it's vetur report. :S

rchl · 2021-12-03T19:35:10Z

🤦 Sorry. That's my default setup and forgot to switch for testing.

But now that I've switched to Volar, it doesn't seem to work with either export default {} or export default Vue.extend({})`.

johnsoncodehk · 2021-12-03T19:36:29Z

Maybe Tutorial.vue is still export default Vue.extend({ ... }). If you change Tutorial.vue from export default Vue.extend({ ... }) to export default { ... }

rchl · 2021-12-03T19:37:56Z

No, you can try yourself on the project. Pushed Vue.extend removal

johnsoncodehk · 2021-12-03T19:39:42Z

Sorry, also need lang="ts".

rchl · 2021-12-03T19:45:52Z

OK, can reproduce that case.

That complicates things since now we have more variables to potentially document.

As far as using plain JS, Vue.extend still seems like a preferred option.

As far as TS, are you saying that it will work only with Vue.extend in the future (based on your comment)? In which case, doesn't my point still stands that using Vue.extend is recommended? Or do you mean that it won't be supported at all. And in that case, only for TS or also JS?

johnsoncodehk · 2021-12-05T11:30:10Z

I think we don’t need to advise users what to use, just state the facts, which methods are supported and which are not.

	Component options type-checking in `<script>`	Interpolation type-checking in `<template>`	Cross-component props type-checking
`export default { ... }` with JS	Not support	Not support	Not support
`export default { ... }` with TS	Not support	Support but planed to abandon in future	Support but planed to abandon in future
`export default Vue.extend({ ... })` with JS	Not support	Not support	Not support
`export default Vue.extend({ ... })` with TS	Limited (Support `data` types but not support `props` types)	Limited	Not support
`export default defineComponent({ ... })`	Support	Support	Support
Class component	Support	Support with additional code (#21)	Support with additional code

rchl · 2021-12-05T19:36:00Z

Is this a typo?

Vue.extend is exactly what is supposed to make those work.

johnsoncodehk · 2021-12-06T08:55:35Z

Vue.extend only working with js but not working with ts on my tests.

You can try:

// test-js.js
import Vue from 'vue'

Vue.extend({
	data: () => ({
		foo: 123
	}),
	mounted() {
		this.foo // any
	},
})

// test-ts.ts
import Vue from 'vue'

Vue.extend({
	data: () => ({
		foo: 123
	}),
	mounted() {
		this.foo // number
	},
})

rchl · 2021-12-06T09:24:44Z

I would swear that JS was working before but it doesn't seem like it. Maybe I was confused due to my Vetur running again...

In that case I would say that Options API Vue2 support is not in a state that is usable in a real world projects so maybe it shouldn't be supported/advertised at all?

Having to add Vue.extend everywhere is one major obstacle. I don't think that it's feasible to do that everywhere in an existing, potentially large projects.

The other issue is that type checking is spotty at best so many of the issues wouldn't be caught. Vetur is not ideal either, mind you, but certainly more complete.

johnsoncodehk · 2021-12-06T10:05:58Z

I would swear that JS was working before but it doesn't seem like it. Maybe I was confused due to my Vetur running again...

I think this has not relate to vetur/volar because it is reproduced in vanilla js/ts.

In that case I would say that Options API Vue2 support is not in a state that is usable in a real world projects so maybe it shouldn't be supported/advertised at all?

With defineComponent from @vue/composition-api I think the support for vue2 is already quite good.

Having to add Vue.extend everywhere is one major obstacle. I don't think that it's feasible to do that everywhere in an existing, potentially large projects.

Users only need to continue to use vetur. If they don't want to modify the code, they don't have to switch to volar.
btw the method I recommend is defineComponent instead of Vue.extend.

The other issue is that type checking is spotty at best so many of the issues wouldn't be caught. Vetur is not ideal either, mind you, but certainly more complete.

Are you talking about using Vue.extend? If yes, it is because vetur has done some work outside of Vue.extend to support more types. But like I said, doing so destroys predictability, so Volar won't do it. The component type will be completely controlled by the vue library. If Vue.extend is missing the props type, the user should not get the props type in the template, otherwise it is a bug for volar.

rchl · 2021-12-06T10:20:20Z

With defineComponent from @vue/composition-api I think the support for vue2 is already quite good.

But I'm talking about the Options API specifically. Can definedComponent be used with Options API? If so then I'm fine with just including that info the readme (the table you've posted).

johnsoncodehk · 2021-12-06T10:23:41Z

Can definedComponent be used with Options API?

Yes, it is comprehensively better than Vue.extend.

yangHeavy · 2022-01-28T06:57:07Z

I think we don’t need to advise users what to use, just state the facts, which methods are supported and which are not.

Component options type-checking in <script> Interpolation type-checking in <template> Cross-component props type-checking
export default { ... } with JS Not support Not support Not support
export default { ... } with TS Not support Support but planed to abandon in future Support but planed to abandon in future
export default Vue.extend({ ... }) with JS Not support Not support Not support
export default Vue.extend({ ... }) with TS Limited (Support data types but not support props types) Limited Not support
export default defineComponent({ ... }) Support Support Support
Class component Support Support with additional code (#21) Support with additional code

hello, i have seen this property table for prop type check.
First, i am Very exciting volar supports the vue2.0 type check.
But what about vue-property-decorator use @prop ? Can it have the type check and auto-complete? It seems belong to class component type.
See the example in this repository: https://github.com/MAG-Christian-Birkl/volar-vue2-test-mag
Although I have add static components: { HelloWorld: typeof HelloWorld }, it still failed with type check.

johnsoncodehk · 2022-01-28T07:16:22Z

@yangHeavy it's a example what you can define in class component for volar.

export default class Foo extends Vue {
  static components: {
    MyComp: typeof MyComp
  }
  $props!: {
    optionalProp?: string;
    requiredProp: string;
  }
  $emit!: {
    (e: 'my-event-1'): void
    (e: 'my-event-2', arg1: string, arg2: number): void
  }
  $scopedSlots!: { // $scopedSlots for vue2, $slots for vue3
    'my-slot-1': () => VNode[]
    'my-slot-2': (bindings: { arg1: string, arg2: number }) => VNode[]
  }
}

yangHeavy · 2022-01-28T08:34:58Z

@johnsoncodehk Thanks for answer for how to use class component with volar. But there some problems too.

I have to use declarations, otherwise I get an error
so vue-property-decorator use @prop can't check?

johnsoncodehk · 2022-01-28T08:42:08Z

@yangHeavy yes you need to define it repeatedly. decorator == no TS support :)

yangHeavy · 2022-01-28T09:26:14Z

@johnsoncodehk I see. But there are some problems when I have defined the variable.
I define it string, use it with number, but volar doesn't get an error.

johnsoncodehk · 2022-01-28T09:28:07Z

@yangHeavy in this case you need to define $props!: { what?: string } additionally.

yangHeavy · 2022-01-28T09:34:27Z

@johnsoncodehk Sorry, I found it. I try it success!! I will share Volar with my colleagues and weigh whether we need to use variable type checking in cases where we need to define it twice. Thank you very much.

johnsoncodehk · 2022-01-28T11:43:10Z

@yangHeavy as a workaround, you could shim the component type to auto define $props.

In this workaround, you need to write readonly additionally to distinguish this is a prop not component data.

@Component({})
class HelloWorld extends Vue {
  @Prop() readonly requiredProp!: string;
  @Prop() readonly optionalProp?: string;
  nonProp?: string;
}

export default HelloWorld as ShimComponentProps<typeof HelloWorld>;

/** equal to
@Component({})
class HelloWorld extends Vue {
  @Prop() readonly requiredProp!: string;
  @Prop() readonly optionalProp?: string;
  nonProp?: string;
  $props!: {
    requiredProp: string,
    optionalProp?: string
  }
}
 */

helper types:

type ShimComponentProps<T extends new (...args: any) => any> = new () => InstanceType<T> & {
  $props: ComponentProps<InstanceType<T>>
};

type ComponentProps<T> =
  { [K in keyof Pick<T, ReadonlyKeys<T> & OptionalKeys<T>>]?: T[K] }
  & { [K in keyof Pick<T, ReadonlyKeys<T> & RequiredKeys<T>>]: T[K] };

type Equal<X, Y> = (<T>() => T extends X ? 1 : 2) extends <T>() => T extends Y ? 1 : 2 ? true : false;

type ReadonlyKeys<
  T,
  U extends Readonly<T> = Readonly<T>,
  K extends keyof T = keyof T
  > = K extends keyof T ? Equal<Pick<T, K>, Pick<U, K>> extends true ? K : never : never;

type OptionalKeys<T> = keyof {
  [K in keyof T as T[K] extends Required<T>[K] ? never : K]: T[K]
};

type RequiredKeys<T> = keyof {
  [K in keyof T as T[K] extends Required<T>[K] ? K : never]: T[K]
};

yangHeavy · 2022-01-29T03:34:34Z

@johnsoncodehk ShimComponentProps is a nice typescript coding example! But it still has some problems after i test it.

ShimComponentProps doesn't extends Vue! And this will cause @components() can't identify HelloWorld.

I think the reason is interface Vue has readonly attr also. And it is set to $props too.

* master: (134 commits) Document recursive components (#1008) refactor: move common TS logic to new package `@volar/vue-typescript` (#1004) chore: update pnpm-lock.yaml v0.32.1 chore: changelog feat: show vite app preview config file fix: vite icon do not show with first editor fix: document symbols confusion between `<script>` and `<script setup>` feat: support generic props events fix: pug last child tag mapping incorrect chore: set minimal vscode version to 1.61.0 fix: auto-import cache logic break langauge server if TS version < 4.4 fix: exclude recursive component type if duplicate name with import components chore: update pnpm-lock.yaml fix: `source.organizeImports` not working in `editor.codeActionsOnSave` fix: slot name mapping range incorrect v0.32.0 chore: changelog feat: experimental webview features fix: don't pack extension with `--minify` flag which break scss formatting ...

rchl · 2022-03-05T22:33:21Z

I've applied your suggestion with some minor changes. Let me know if it looks better now.

johnsoncodehk · 2022-03-06T11:52:16Z

LGTM, thank you!

hexf00 · 2022-05-18T10:03:30Z

@yangHeavy it's a example what you can define in class component for volar.

export default class Foo extends Vue {
  static components: {
    MyComp: typeof MyComp
  }
  $props!: {
    optionalProp?: string;
    requiredProp: string;
  }
  $emit!: {
    (e: 'my-event-1'): void
    (e: 'my-event-2', arg1: string, arg2: number): void
  }
  $scopedSlots!: { // $scopedSlots for vue2, $slots for vue3
    'my-slot-1': () => VNode[]
    'my-slot-2': (bindings: { arg1: string, arg2: number }) => VNode[]
  }
}

In vue2 project, the type of scope parameter is deduced as vnode [] | undefined, I want to know what happened in the middle, or does it not have this feature?

hexf00 · 2022-05-18T16:47:05Z

@yangHeavy it's a example what you can define in class component for volar.

export default class Foo extends Vue {
  static components: {
    MyComp: typeof MyComp
  }
  $props!: {
    optionalProp?: string;
    requiredProp: string;
  }
  $emit!: {
    (e: 'my-event-1'): void
    (e: 'my-event-2', arg1: string, arg2: number): void
  }
  $scopedSlots!: { // $scopedSlots for vue2, $slots for vue3
    'my-slot-1': () => VNode[]
    'my-slot-2': (bindings: { arg1: string, arg2: number }) => VNode[]
  }
}

In vue2 project, the type of scope parameter is deduced as vnode [] | undefined, I want to know what happened in the middle, or does it not have this feature?

https://github.com/johnsoncodehk/volar/tree/master/extensions/vscode-vue-language-features

I followed the steps prompted in the document and found that the type overload of Vue needs to be deleted. The slot parameter type prompt of volar can take effect

aziztitu · 2022-10-12T07:34:42Z

@johnsoncodehk I was able to follow your instructions and get the type checking for Props and ScopedSlots working, but for the Emit, it seems like there might be a type mismatch.

In the Vue types package, it looks like $emit expects a Function type.

Should we override a different variable other than $emit instead?

johnsoncodehk · 2022-10-12T07:42:40Z

@aziztitu Vue 2 do not support typed emit, if you do want to, you can try omit $emit from Vue interface.

aziztitu · 2022-10-12T08:01:56Z

@johnsoncodehk Gotcha. I was able to at least get the Event suggestions working by hacking it like this:

This stops any errors from being thrown, but the only issue is there's no actual type checking happening. It seems to think that all events now take 2 args :D

But it probably is just due to the fact that it's using the args from the last match. I can just remove the args from the Emit type, and live with it for now :)

johnsoncodehk · 2022-10-12T08:11:48Z

@aziztitu please track #1855

fix(docs): extend vue 2 info regarding types

2b02064

Related #741

johnsoncodehk force-pushed the master branch from 25798c7 to 87e1627 Compare December 15, 2021 06:42

johnsoncodehk force-pushed the master branch 7 times, most recently from 9f58be3 to 560b89b Compare December 31, 2021 19:30

rchl added 2 commits March 5, 2022 23:12

update instructions as suggested

a49a153

johnsoncodehk merged commit 37deac7 into vuejs:master Mar 6, 2022

rchl deleted the fix/vue-2-info branch March 6, 2022 12:33

This was referenced Mar 11, 2022

after update to 0.32.1, component event has payload type error #1001

Closed

No support for combination of Nuxt 2 and vue-class-component? #1061

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sbarfurth mentioned this pull request Mar 22, 2022

Cannot type $emit on class style components #1097

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hexf00 mentioned this pull request May 18, 2022

How to disabled line for VTI or VLS vuejs/vetur#3010

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johnsoncodehk mentioned this pull request Jun 7, 2022

JSX element type does not have any construct or call signatures.ts(2604) #1405

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fix(docs): extend vue 2 info regarding types #750

fix(docs): extend vue 2 info regarding types #750

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