What is the correct way to utilize the mapState function within a TypeScript environment while implementing Vuex?

Question

What is the correct way to utilize the mapState function within a TypeScript environment while implementing Vuex?

In my Vue.js project integrated with Vuex, I am using Typescript syntax. While trying to use the mapState method as computed in my .ts file, I encountered a syntax error. Currently, I am following the suggested syntax for computed function in the documentation:

 get counter() {
   return  this.$store.state.count;
 }

However, it is mentioned in the Vuex docs that using mapState instead of the above method is more efficient and less repetitive, especially in large applications. I attempted to use mapState in my Typescript component but failed to do so. Here are some unsuccessful attempts:

get mapState({
  counter:count
});

// or

get mapState(['name', 'age', 'job'])

If anyone could provide assistance on the correct way to use mapState in Typescript components, I would greatly appreciate it.

typescript vuejs2 vuex

Answer 1

Answer №1

To access mapState within the Component annotation, you can simply do the following:

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

@Component({
  // If you are not using namespaced modules, you can omit the 'myModule' argument
  computed: mapState('myModule', [ 
    'count',
  ]),
})
export default class MyComponent extends Vue {
  public count!: number; // This value is assigned through mapState
}

Additionally, mapState can be utilized to generate new computed properties based on your state:

import { Component, Vue } from 'vue-property-decorator';
import { mapState } from 'vuex';
import { IMyModuleState } from '@/store/state';

@Component({
  computed: mapState('myModule', {
    // Assuming IMyModuleState.items exists
    countWhereActive: (state: IMyModuleState) => state.items.filter(i => i.active).length,
  }),
})
export default class MyComponent extends Vue {
  public countWhereActive!: number; // This value is assigned through mapState
}

Answer 2

To access mapState within the Component annotation, you can simply do the following:

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

@Component({
  // If you are not using namespaced modules, you can omit the 'myModule' argument
  computed: mapState('myModule', [ 
    'count',
  ]),
})
export default class MyComponent extends Vue {
  public count!: number; // This value is assigned through mapState
}

Additionally, mapState can be utilized to generate new computed properties based on your state:

import { Component, Vue } from 'vue-property-decorator';
import { mapState } from 'vuex';
import { IMyModuleState } from '@/store/state';

@Component({
  computed: mapState('myModule', {
    // Assuming IMyModuleState.items exists
    countWhereActive: (state: IMyModuleState) => state.items.filter(i => i.active).length,
  }),
})
export default class MyComponent extends Vue {
  public countWhereActive!: number; // This value is assigned through mapState
}

Answer 3

Answer №2

Utilizing JS Spread syntax for simplification:

<template>
  <div class="hello">
    <h2>{{ custom }}</h2>
    </div>
</template>

<script lang="ts">
import { Component, Prop, Vue } from 'vue-property-decorator';
import { mapState } from 'vuex';

@Component({
  computed: {
    ...mapState({
      title: 'stuff'
    }),
    // other stuff
  },
})
export default class HelloWorld extends Vue {

  title!: string;

  public get custom():string {
    return this.title;
  }
}
</script>

Your store:

import Vue from 'vue';
import Vuex from 'vuex';

Vue.use(Vuex);

export default new Vuex.Store({
  state: {
    stuff: 'some title',
  },
  mutations: {

  },
  actions: {

  },
});

Answer 4

Utilizing JS Spread syntax for simplification:

<template>
  <div class="hello">
    <h2>{{ custom }}</h2>
    </div>
</template>

<script lang="ts">
import { Component, Prop, Vue } from 'vue-property-decorator';
import { mapState } from 'vuex';

@Component({
  computed: {
    ...mapState({
      title: 'stuff'
    }),
    // other stuff
  },
})
export default class HelloWorld extends Vue {

  title!: string;

  public get custom():string {
    return this.title;
  }
}
</script>

Your store:

import Vue from 'vue';
import Vuex from 'vuex';

Vue.use(Vuex);

export default new Vuex.Store({
  state: {
    stuff: 'some title',
  },
  mutations: {

  },
  actions: {

  },
});

What is the correct way to utilize the mapState function within a TypeScript environment while implementing Vuex?

Answer №1

Answer №2

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