vuex-effects

Effects is a side effect model for Vuex. Effects use subscribers to provide new sources of actions such as network requests, web socket messages and time-based events.

• Basic example

Installation

$ npm install vuex-effects

Usage

Import Plugin

import VuexEffects from "vuex-effects";

Vue.use(VuexEffects(store));

Use this in component like this

import { mapActions, mapState } from 'vuex';

export default {
  // ...
  effects: {
    actions: {
      getTasksList: {
        after(action, state) {
          localStorage.setItem('tasksList', JSON.stringify(this.tasksList));
        }
      }
    }
  },
  // ...
  computed: {
    ...mapState(['tasksList']),
  },
  mounted() {
    this.getTasksList();
  },
  methods: {
    ...mapActions(['getTasksList']),
  },
};

Use this outside component (global effects) like this

// @/src/store/tasksEffects.js
export default {
  effects: {
    actions: {
      getTasksList: {
        after(action, state) {
          localStorage.setItem('tasksList', JSON.stringify(this.tasksList));
        }
      }
    }
  },
};

If your effects is outside component (global effects) then you must include your global effects in second parameter

// main.js
// ...
import VuexEffects from "vuex-effects";
import tasksEffects from '@/store/effets/tasksEffects';
Vue.use(VuexEffects(store, [tasksEffects])); 
// ...

Effects Options

Actions

By default action effects is called before action dispatched if you pass your effect like a function and receives the action descriptor and current store state as arguments.

Let's look at this example effects:

effects: {
    actions: {
        getTasksList(action, state) {
            // this code invokes BEFORE vuex action has finished 
            localStorage.setItem('tasksList', JSON.stringify(this.tasksList));
        }
    }
}

If you want to invoke your effects after vuex action, you must to use object notation like this

effects: {
    actions: {
        getTasksList: {
            before(action, state) {
                // this code invokes BEFORE vuex action has finished 
                localStorage.setItem('tasksListBefore', JSON.stringify(this.tasksList));
            },
            after(action, state) {
                // this code invokes AFTER vuex action has finished 
                localStorage.setItem('tasksListAfter', JSON.stringify(this.tasksList));
            }
        }
    }
}

By default, new actions effects is added to the end of the chain, so it will be executed after other effects that were added before. This can be overridden by adding prepend: true to options, which will add the handler to the beginning of the chain.

Let's look at this example effects:

effects: {
    actions: {
        getTasksList: {
            prepend: true, // this will add your effects to the beginning of the chain
            after(action, state) {
                // this code invokes AFTER vuex action has finished 
                localStorage.setItem('tasksListAfter', JSON.stringify(this.tasksList));
            }
        }
    }
}

You can also use handler as an alias for before

effects: {
    actions: {
        getTasksList: {
            prepend: true, // this will add your effects to the beginning of the chain
            handler(action, state) { // same as before()
                // this code invokes BEFORE vuex action has finished 
                localStorage.setItem('tasksListAfter', JSON.stringify(this.tasksList));
            }
        }
    }
}

For using it with namespaced state

effects: {
    actions: {
        'tasks/getTasksList': { // this is an analogy for mapActions argument
            prepend: true, // this will add your effects to the beginning of the chain
            handler(action, state) { // same as before()
                // this code invokes BEFORE vuex action has finished 
                localStorage.setItem('tasksListAfter', JSON.stringify(this.tasksList));
            }
        }
    }
}

Mutations

Mutations effects is called after every mutation and receives the mutation descriptor and post-mutation state as arguments. Mutations doesn't have before and after methods unlike Actions, only the handler method is avalable in object notation.

Let's look at this example effects:

effects: {
    mutations: {
        setTasksList(mutation, state) {
            // this code invokes AFTER vuex mutation has finished 
            console.log(mutation.payload)
            console.log(state)
        }
    }
}

By default, new mutations effects is added to the end of the chain, so it will be executed after other mutations effects that were added before. This can be overridden by adding prepend: true to options, which will add the handler to the beginning of the chain.

Let's look at this example effects:

effects: {
    mutations: {
        getTasksList: {
            prepend: true, // this will add your effects to the beginning of the chain
            handler(mutation, state) {
                // this code invokes AFTER vuex mutation has finished 
                localStorage.setItem('tasksListAfter', JSON.stringify(this.tasksList));
            }
        }
    }
}