Version

"vue": "^3.0.0" "eslint": "^6.7.2" "typescript": "~3.9.3" vue-cli@latest

Reproduction link

Steps to reproduce

import { defineComponent, PropType } from "vue";

interface ComplexMessage {
  title: string;
  okMessage: string;
  cancelMessage: string;
}

const BarCharts = defineComponent({
  setup() {},
  props: {
    message: {
      type: Object as PropType<ComplexMessage>,
      required: true,
      validator(message: ComplexMessage) {
        return !!message.title;
      }
    }
  },
  data() {
    return {};
  },
  created() {
    console.log(this.message); // ts2339
  },
  render() {
    return <div>1</div>;
  }
});

export default BarCharts;

What is expected?

No ts warning

What is actually happening?

ts warning show: Property 'message' does not exist on type 'ComponentPublicInstance<Readonly<{ [x: number]: string; } & { length?: number | undefined; toString?: string | undefined; toLocaleString?: string | undefined; concat?: string[] | undefined; join?: string | undefined; ... 17 more ...; flat?: unknown[] | undefined; }> | Readonly<...>, ... 8 more ..., ComponentOptionsB...'. Property 'message' does not exist on type '{ $: ComponentInternalInstance; $data: {}; $props: Readonly<{ [x: number]: string; } & { length?: number | undefined; toString?: string | undefined; toLocaleString?: string | undefined; ... 19 more ...; flat?: unknown[] | undefined; }> | Readonly<...>; ... 10 more ...; $watch(source: string | Function, cb: Function,...'.ts(2339)

file name: BarCharts.tsx, use vscode vetur@latest.

This is fine.

but : https://v3.vuejs.org/guide/component-props.html#prop-validation

You should use arrow function while using validator or default attr. #2474

You should use arrow function while using validator or default attr. #2474

This answer is correct.

I'm having the same problem, but with data instead of props. I don't have any validators or anything like that, and it works just fine when using javascript.

<script lang="ts">
export default {
  data() {
    return {
      platform: "x86_64"
    };
  },
  computed: {
    showMachines() {
      return this.platform === "arm" || this.platform === "aarch64"; // Error here, on platform
    },
    showAarch64() {
      return this.platform === "aarch64"; // Here too, same place
    }
  }
};
</script>

1. use defineComponent() to let TS know you are actually defining a Vue component
2. try annotating the return values of the computed's:

showMachines(): boolean {

For more help, please use chat.vuejs.org

I'm having the same problem, but with data instead of props. I don't have any validators or anything like that, and it works just fine when using javascript.

<script lang="ts">
export default {
  data() {
    return {
      platform: "x86_64"
    };
  },
  computed: {
    showMachines() {
      return this.platform === "arm" || this.platform === "aarch64"; // Error here, on platform
    },
    showAarch64() {
      return this.platform === "aarch64"; // Here too, same place
    }
  }
};
</script>

The same problem with you. It's confused.

https://v3.vuejs.org/guide/typescript-support.html#annotating-return-types

@ravenclaw900 @bobohuochai as @LinusBorg point as soon you define the return types of your computed properties the types from the data properties will work just fine(looks like not doing it breaks all the typing on the component).

1. use defineComponent() to let TS know you are actually defining a Vue component
2. try annotating the return values of the computed's:

showMachines(): boolean {

For more help, please use chat.vuejs.org

thank you very much!

1. use defineComponent() to let TS know you are actually defining a Vue component
2. try annotating the return values of the computed's:

showMachines(): boolean {

For more help, please use chat.vuejs.org

This works. The problem of TypeScript

I had this problem for objects that I was injecting into my component. For anyone having problems with typing injected data, the solution is to use the Composition API instead.

1. use defineComponent() to let TS know you are actually defining a Vue component
2. try annotating the return values of the computed's:

showMachines(): boolean {

For more help, please use chat.vuejs.org

thanks, also correct resolve my problem, ts error with data.