内容简介:In one of myprevious articles, I mentioned how it is possible to design a simple state manager in Vue by usingIn Vue 2, a reactive store might look like this:We can provide the components with a basic
In one of myprevious articles, I mentioned how it is possible to design a simple state manager in Vue by using observable . The Observable API has been available in Vue since version 2 however, with version 3 the reactive object is no longer directly modified but proxied into. Let's have a look how both work in detail:
In Vue 2, a reactive store might look like this:
// store.js
export const store = Vue.observable({ orders: 0 });
We can provide the components with a basic dispatch function that will collect an action with a payload and that will take care of updating the state. Also, we might want to provide a getters helper so that the store values can be reached as computed properties:
// store.js
export function dispatch(type, payload) {
switch(type) {
case 'increment-orders':
Object.assign(store, { orders: store.orders + payload });
break;
default:
//
}
}
export function getters(orders) {
return {
orders: () => store.orders
}
}
In our Vue component, we register the getters and use dispatch to notify the store about a user event:
<template>
I have {{ orders }} orders on my account.
<a @click="increment()">add order</a>
</template>
<script>
import { dispatch } from 'store';
return {
computed: { ...getters() },
methods: {
increment() {
dispatch('increment-orders', 1);
}
}
};
</script>
Vue 3 and the Composition API
With the introduction of the Composition API , operating with reactive properties is much simpler. The above example could be easily refactored to follow the new constructs. Here, reactive replaced the functionaltiy that observable was providing:
// store.js
import { reactive } from 'vue';
export const store = reactive({ orders: 0 });
// Component.vue
import { store, dispatch } from './store';
export default {
setup() {
return { store };
},
methods:{
increment() {
dispatch('increment-orders', 1);
}
}
}
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