vue-class-component & Mixins

Question

I use vue-class-component with TypeScript for my Vue project. I have the component and the Mixin for it:

// MyComp.vue
import Component, { mixins } from 'vue-class-component'
import MyMixin from './mixin.ts'

@Component
export class MyComp extends mixins(MyMixin) {
  compValue: string = 'Hello';
}


// mixin.ts
import Vue from 'vue'
import Component from 'vue-class-component'

@Component
export default class MyMixin extends Vue {
  created() {
    console.log(this.compValue); // TS2339: Property 'compValue' does not exist on type 'MyMixin'.
  }
}

It works, but TypeScript complains about missing Property 'compValue'. How to fix this problem?

Answer 1

The error happens because compValue doesn't exist in MyMixin . In case this is abstract class that is never instantiated on its own and it's guaranteed the property is there, it can be declared:

export default class MyMixin extends Vue {
  compValue: string;
  created() {
    console.log(this.compValue);
  }
}