vuex-helpers

• Description
• Usage
• Methods
  • mapInstance* Helpers

Description

This library is a collection of small utility/helper functions to make working with Vuex easier.

Usage

Install and save the library:

npm install --save @urbn/vuex-helpers

Methods

mapInstance* Helpers

The mapInstance* helpers are 4 helper functions that correspond to existing Vuex Component Binding Helper functions but allow the consumer to use a function to determine a dynamic Vuex module namespace at runtime:

• mapInstanceState
• mapInstanceGetters
• mapInstanceMutations
• mapInstanceActions

For example, normally we would use the methods provided by Vuex for static namespaces:

const store = new Vuex.Store({
    modules: {
        auth: {
            namespaced: true,
            state: {
                loggedIn: false,
            },
        },
    },
});

export default {
    name: 'MyComponent',
    computed: {
        ...mapState('auth', {
            loggedIn: state => state.loggedIn,
        }),
    },
};

However, this does not work if you are using dynamically generated namespaces. Consider using a product module for multiple products in an e-commerce application:

const productModule = {
    namespaced: true,
    state: () => ({
        name: null,
        price: null,
    }),
    mutations: { ... },
};

// At runtime, we may dynamically create multiple modules per product:
store.registerModule(`product-${slug1}`, productModule);
store.registerModule(`product-${slug2}`, productModule);

Once we've done this, we can no longer leverage the map* helpers because we have no way to make the namespace dynamic. This is the problem solved by the mapInstance* helpers, in that they let you provide a function that takes your component instance as an argument and you can return a dynamic Vuex module namespace.

Assume we are rendering components as such:

<MyProduct :slug="slug1" />
<MyProduct :slug="slug2" />

Then inside MyProduct we can choose the proper namespaced Vuex module using a namespace function:

const getNamespace = cmp => `product-${cmp.slug}`;

export default {
    name: 'MyProduct',
    props: ['slug'],
    computed: {
        ...mapInstanceState(getNamespace, {
            name: state => state.name,
            price: state => state.price,
        }),
    },
};

It should be noted that these helpers are trying to solve a denied feature request in the core Vuex library.