Vue JS TypeScript component is unable to locate injected instance properties

Question

Vue JS TypeScript component is unable to locate injected instance properties

Currently, I'm utilizing typescript alongside vue in my project.

Within the app structure, there exists a service that acts as a global entity for all sub-components.

I stumbled upon this native solution provided by Vue JS, which facilitates injecting this property into child components.

In the main.ts file:

const service = new MyService(...);

new Vue({
  router,
  provide() { return { service }; } // providing the service for injection
  render: h => h(App),
}).$mount("#app");

For any typescript vue component:

import Vue from "vue";

export default Vue.extend({
  inject: ["service"], // injecting the service
  mounted() {
    console.log(this.service); // access to this.service is available 
  },
});

By following this method, I am successfully able to acquire the injected service within my Child components.

However, an error message is being displayed:

Error - 'Property 'service' does not exist on type 'CombinedVueInstance < Vue, {}, {}, {}, Readonly < Record < never, any > > >'.'

What steps can be taken to rectify this typescript compilation error?

javascript typescript vue.js vuejs2

Answer 1

Answer №1

To achieve this, you do not necessarily have to use class components. There are two methods for declaring object components:

Adjusting data return type

export default {
  inject: ['myInjection'],
  data(): { myInjection?: MyInjection } {
    return {}
  },
}

However, the drawback is that you must mark it as optional in order to add it to the data return.

Expanding Vue context

declare module 'vue/types/vue' {
  interface Vue {
    myInjection: MyInjection
  }
}

export default {
  inject: ['myInjection'],
}

Answer 2

To achieve this, you do not necessarily have to use class components. There are two methods for declaring object components:

Adjusting data return type

export default {
  inject: ['myInjection'],
  data(): { myInjection?: MyInjection } {
    return {}
  },
}

However, the drawback is that you must mark it as optional in order to add it to the data return.

Expanding Vue context

declare module 'vue/types/vue' {
  interface Vue {
    myInjection: MyInjection
  }
}

export default {
  inject: ['myInjection'],
}

Answer 3

Answer №2

Utilizing plugins

If you want to incorporate a specific service across all Vue components, consider leveraging plugins.
Simply import it in your main.ts file:

import Vue from "vue";
import "@/plugins/myService";

In the plugins/myService.ts file, ensure to include something similar to this:

import _Vue from "vue";
import MyService from "@/services/MyService";

export default function MyServicePlugin(Vue: typeof _Vue, options?: any): void {
    Vue.prototype.$myService = new MyService(...); // You can access 'service' from other locations as well
}

_Vue.use(MyServicePlugin);

You can now make use of this service in any Vue component:

<template>
  <div> {{ $myService.name }}</div>
</template>
<script lang="ts">
  import { Component, Vue } from "vue-property-decorator";
  
  @Component
  export default class MyComponent extends Vue {
    private created() {
      const some = this.$myService.getStuff();
    }
  }
</script>

Do not overlook declaring $myService within a d.ts file. Introduce a file named myService.d.ts in your project with the subsequent content:

import MyService from "@/services/MyService";

declare module "vue/types/vue" {
  interface Vue {
      $myService: MyService;
  }
}

Answer 4

Utilizing plugins

If you want to incorporate a specific service across all Vue components, consider leveraging plugins.
Simply import it in your main.ts file:

import Vue from "vue";
import "@/plugins/myService";

In the plugins/myService.ts file, ensure to include something similar to this:

import _Vue from "vue";
import MyService from "@/services/MyService";

export default function MyServicePlugin(Vue: typeof _Vue, options?: any): void {
    Vue.prototype.$myService = new MyService(...); // You can access 'service' from other locations as well
}

_Vue.use(MyServicePlugin);

You can now make use of this service in any Vue component:

<template>
  <div> {{ $myService.name }}</div>
</template>
<script lang="ts">
  import { Component, Vue } from "vue-property-decorator";
  
  @Component
  export default class MyComponent extends Vue {
    private created() {
      const some = this.$myService.getStuff();
    }
  }
</script>

Do not overlook declaring $myService within a d.ts file. Introduce a file named myService.d.ts in your project with the subsequent content:

import MyService from "@/services/MyService";

declare module "vue/types/vue" {
  interface Vue {
      $myService: MyService;
  }
}

Answer 5

Answer №3

Implementing Vue property decorators

Vue-property-decorator, an extension that inherits decorators from vue-class-component, provides a range of TypeScript decorators that enhance intellisense. These decorators are best utilized with the class API.

@Inject and @Provide are among these useful decorators:

In the provider component:

import {Vue, Component, Provide} from 'vue-property-decorator';

@Component
export default class MyClass {
  @Provide('service') service: Service = new MyServiceImpl(); // or any other implementation
}

In the component receiving the provided service:

import {Vue, Component, Inject} from 'vue-property-decorator';

@Component
export default class MyClass {
  @inject('service') service!: Service; // or specific type for this service
  mounted() {
    console.log(this.service); // no TypeScript errors here
  },
}

This approach offers optimal intellisense when working with Vue.

However, in certain scenarios where modifying all components is not feasible, you can use a workaround like:

Typecasting "this"

You have the option to cast this to any before accessing this.service. While not ideal, it gets the job done:

  mounted() {
    console.log((this as any).service);
  },

There may be alternative methods available, but I am more inclined towards using the class API along with vue-property-decorators for superior intellisense benefits.

Answer 6

Implementing Vue property decorators

Vue-property-decorator, an extension that inherits decorators from vue-class-component, provides a range of TypeScript decorators that enhance intellisense. These decorators are best utilized with the class API.

@Inject and @Provide are among these useful decorators:

In the provider component:

import {Vue, Component, Provide} from 'vue-property-decorator';

@Component
export default class MyClass {
  @Provide('service') service: Service = new MyServiceImpl(); // or any other implementation
}

In the component receiving the provided service:

import {Vue, Component, Inject} from 'vue-property-decorator';

@Component
export default class MyClass {
  @inject('service') service!: Service; // or specific type for this service
  mounted() {
    console.log(this.service); // no TypeScript errors here
  },
}

This approach offers optimal intellisense when working with Vue.

However, in certain scenarios where modifying all components is not feasible, you can use a workaround like:

Typecasting "this"

You have the option to cast this to any before accessing this.service. While not ideal, it gets the job done:

  mounted() {
    console.log((this as any).service);
  },

There may be alternative methods available, but I am more inclined towards using the class API along with vue-property-decorators for superior intellisense benefits.

Answer 7

Answer №4

Enhance Vue Functionality for Injected Components Only

To optimize Vue performance, create a specialized interface for injection and extend Vue solely for the specific components requiring it:

main.ts:

const customService = new CustomService(...);

export interface ServiceInjector {
  service: CustomService;
}

new Vue({
  router,
  provide(): ServiceInjector { return { service: customService }; } // provide the injected service
  render: h => h(App),
}).$mount("#app");

An example component utilizing your interface:

import Vue from "vue";
import { ServiceInjector } from 'main.ts';

export default ( Vue as VueConstructor<Vue & ServiceInjector> ).extend({
  inject: ["service"], // inject the specialized service
  mounted() {
    console.log(this.service); // verify that this.service is available 
  },
});

Answer 8

Enhance Vue Functionality for Injected Components Only

To optimize Vue performance, create a specialized interface for injection and extend Vue solely for the specific components requiring it:

main.ts:

const customService = new CustomService(...);

export interface ServiceInjector {
  service: CustomService;
}

new Vue({
  router,
  provide(): ServiceInjector { return { service: customService }; } // provide the injected service
  render: h => h(App),
}).$mount("#app");

An example component utilizing your interface:

import Vue from "vue";
import { ServiceInjector } from 'main.ts';

export default ( Vue as VueConstructor<Vue & ServiceInjector> ).extend({
  inject: ["service"], // inject the specialized service
  mounted() {
    console.log(this.service); // verify that this.service is available 
  },
});

Vue JS TypeScript component is unable to locate injected instance properties

Answer №1

Adjusting data return type

Expanding Vue context

Answer №2

Utilizing plugins

Answer №3

Implementing Vue property decorators

Typecasting "this"

Answer №4

Enhance Vue Functionality for Injected Components Only

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