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vuex-rest-api

A Helper utility to simplify the usage of REST APIs with Vuex 2. Uses the popular HTTP client axios for requests. Works with websanova/vue-auth.

Table of Contents

• What is this good for
• Installation
• Steps
• API
  • constructor(options:Object):Vapi
  • add(options):Vapi
  • getStore(options):Object
• Miscellaneous
  • Calling the actions
  • Query params
  • Add additional state, actions and mutations to the store
  • Usage with websanova/vue-auth
  • Check error and loading state of requests
  • Changelog

What is this good for

If you want to connect a REST API with Vuex you'll find that there are a few repetitive steps. You need to request the data from the api (with an action) and set the state (via a mutation). This utility (for the sake of brevity called Vapi in the README) helps in creating the store by setting up the state, mutations and actions with a easy to follow pattern.

It is not a middleware.

It's just a helper utility to help prepraring the store object for you. If there's something you don't like just overwrite the property.

Installation

npm install vuex-rest-api

Some notes: This readme assumes that you're using at least ES2015.

Steps

1. Import vuex-rest-api (I called it Vapi).
2. Create a Vapi instance.
   At least you have to set the base URL of the API you're requesting from. You can also define the default state. If you don't define a default state from a property it will default to null. In the example
3. Create the actions.
   Each action represents a Vuex action. If it will be called (property action), it requests a specific API endpoint (property path) and sets the related property named property to the response's payload.
4. Create the store object
5. Pass it to Vuex. Continue reading here to know how to call the actions.

// store.js

import Vuex from "vuex"
import Vue from "vue"
// Step 1
import Vapi from "vuex-rest-api"

Vue.use(Vuex)

// Step 2
const posts = new Vapi({
  baseURL: "https://jsonplaceholder.typicode.com",
    state: {
      posts: []
    }
  })
  // Step 3
  .get({
    action: "getPost",
    property: "post",
    path: ({ id }) => `/posts/${id}`
  })
  .get({
    action: "listPosts",
    property: "posts",
    path: "/posts"
  })
  .post({
    action: "updatePost",
    property: "post",
    path: ({ id }) => `/posts/${id}`
  })
  // Step 4
  .getStore()

// Step 5
export const store = new Vuex.Store(posts)

API

The following sections explain the API of the Vapi class.

constructor(options:Object):Vapi

Creates a new Vapi instance and returns it.

const vapi = new Vapi(options)

The parameter options consists of the following properties:

# axios

• Type: axios (instance)
• Default: axios (instance)
• Usage: The axios instance to use for the requests. This is pretty useful if you use a package like websanova/vue-auth which sets automatically the Authorization header. So you don't need to care. If you don't pass an instance, it will use the global axios instance.

# baseURL

• Type: string

• Usage: The API's base URL without a specific endpoint's path. It's usage is optional. If you don't set it, it will use the base URL of the axios instance. Please note that baseURL has a higher priority than the baseURL set in the passed axios instance. You can also set base URL in the request config when you add an action. The priority is as following:

  baseURL > axios instance base URL > request config base URL

{
  baseURL: "https://jsonplaceholder.typicode.com"
}

# queryParams

• Type: boolean
• Default: If you don't set a property's default value the value is null.
• Usage: If you want to append the params to the request URL, set this property to true. You can also set this option in every action you need it if you don't need it for every action.

{
  queryParams: true
}

# state

• Type: Object
• Default: Every property will default to null.
• Usage: The default state of your properties.

{
  state: {
    post: null, // this is unnecessary (default is null)
    posts: []
  }
}

Sets post to null and posts to an empty array.

add(options):Vapi

Adds an action to access an API endpoint and returns the Vapi instance.

The parameter options consists of the following properties:

# action (required)

• Type: string
• Usage: The name of the action.

{
  action: "getPosts"
}

# method

• Type: string
• Default: "get"
• Usage: The HTTP method to request the API. Following HTTP Methods are allowed at the moment:
  • get
  • delete
  • head
  • post
  • put
  • patch

{
  method: "get"
}

shorthand syntax

You can also use the http method instead of add to omit to set the options.method like this. This works with get, delete, post, put and patch:

// regular way
vrap.add({
  method: "delete"
  // other options...  
})

//shorthand
vrap.delete({
  // other options...
})

# property

• Type: string
• Default: null
• Usage: The property of the state which should be automatically changed if the resolve is successfully.

{
  property: "posts"
}

When to set property in spite of it's optionality

Sometimes you have to set the state by yourself. In that case you may consider to avoid setting property. Please consider the following consequences:

• state.pending.<property name> and state.error.<property name> won't be set. So you can't check these properties to see if the request is still pending or failed. Nevertheless you can still set the onError property to react to the error case.
• Because the property's name is unknown vuex-rest-api can't set the initial state for this property. You have to set the initial state by yourself.
• In the case of successful requests there will be nothing done with the payload. You have to set the onSuccess method to set the state (with the payload) by yourself.

# path (required)

• Type: Function|string
• Usage: This property can either be a function or a path describing the rest of the API address (without the base URL).

Usage with a function

Here we pass a custom path function. This is necessary, because we also need to pass an id. Please note that id is passed in an object. This is necessary because you could pass multiple arguments.

{
  path: ({id}) => `/post/${id}`
}

Usage with a string

Maybe the API endpoint needs no parameters. Then you can use a string like this:

{
  path: "/posts"
}

# headers

• Type: Function|Object
• Usage: This property allows to provide dynamic headers for every request. It can either be a function or an object.

Usage with a function

Here we pass a custom headers function. This allows us to change the extra headers for each request. The data has to be passed over the params bag.

Please note that headers provided via this property will override it's counterpart you maybe set via requestConfig.headers.

// setting the header
{
  headers: ({foo, bar}) => ({
      "FOO": foo,
      "BAR": bar
    })
}

// calling the mapped action and passing the data over the params object
this.getPosts({
  params: { 
    foo: "foo-header",
    bar: "bar-header"
  } 
})

Usage with a string

If the headers don't have to be evaluted on every request, just pass them via an object. Alternatively you could also set the headers via the requestConfig.headers property.

{
  headers: {
    "FOO": "foo-header",
    "BAR": "bar-header"
  }
}

# beforeRequest

• Type: Function
• Default: undefined
• Usage: This function will be called before resolving the action, so you can update the state optimistically. If you need to handle the rejected/resolved response just use the onSuccess and onError functions.

{
  beforeRequest: (state, { params, data }) => {
    state.posts = state.posts.filter(post => post.id !== params.id)
  }
}

# onSuccess

• Type: Function
• Default: undefined
• Usage: This function will be called after successfully resolving the action. If you define this property, only the corresponding pending and error properties will be set, but not state[property].

{
  onSuccess: (state, payload, axios) => {
    // if you set the onSuccess function you have to set the state manually
    state.posts = payload.data
    state.post = payload.data[0]
  }
}

# onError

• Type: Function
• Default: undefined
• Usage: This function will be called if the action request fails. If you define this property, only the corresponding pending and error properties of the set property will be set, but not state[property].

{
  onError: (state, error, axios) => {
    Toast.showError(`Oops, there was following error: ${error}`)

    // if you set the onError function you have to set the state manually
    state.post = null
  }
}

# requestConfig

• Type: Object
• Default: {}
• Usage: An axios.requestConfig object. Please note that the passed HTTP method (see options.method above) won't be changed.

{
  requestConfig: {
    //excerpt from (https://github.com/mzabriskie/axios#request-config)
    // `paramsSerializer` is an optional function in charge of serializing `params`
    // (e.g. https://www.npmjs.com/package/qs, http://api.jquery.com/jquery.param/)
    paramsSerializer: function(params) {
      return Qs.stringify(params, {arrayFormat: 'brackets'})
    },
  }
}

# queryParams

• Type: boolean
• Default: undefined
• Usage: If you want to append the params to the request URL, set this property to true.

{
  queryParams: true
}

getStore(options):Object

Creates an object you can pass to Vuex to add a store.

The parameter options consists of the following properties:

# createStateFn

• Type: boolean
• Default: false
• Usage: Decides if the state should be returned as a function or an object. This option has to be changed if you want to share the state of your created store. Read chapter module reuse in the Vuex documentation for more details.

{
  createStateFn: false
}

The returned object looks like this if you would call it with the settings of the example:

{
  state: {
    pending: {
      posts: false,
      post:  false
    },
    error: {
      posts: null,
      post:  null
    },
    posts:   [],
    post:    null
  }),
  mutations: {
    LIST_POSTS:            Function,
    LIST_POSTS_SUCCEEDED:  Function,
    LIST_POSTS_FAILED:     Function,
    GET_POST:              Function,
    GET_POST_SUCCEEDED:    Function,
    GET_POST_FAILED:       Function,
    UPDATE_POST:           Function,
    UPDATE_POST_SUCCEEDED: Function,
    UPDATE_POST_FAILED:    Function
  },

  //every action's signatures is function(params, data)
  actions: {
    listPosts:  Function,
    getPost:    Function,
    updatePost: Function
  }
}

As you can see, it just created the store for us. No more, no less.

Miscellaneous

Calling the actions

Please respect the following function signature if you want to call an action:

// direct via store
this.$store.dispatch("actionName", { params: {}, data: {} })

// or with mapActions
this.actionName({ params: {}, data: {} })`

params (optional) represents the data you passed to the path property. data (optional) is your request's payload.

Please note that you do not have to set params, data or the enclosing object if you don't need them.

Examples:

• If you want to request all posts with the action listPosts and don't have any data or params, you could call it like this:

// direct via store
this.$store.dispatch("listPosts")

// or with mapActions
this.listPosts()

• If you want to fetch a specific post with an parameter named id call one of the following:

// direct via store
const params = { id: 42 }
this.$store.dispatch("getPost", { params })

// or with mapActions
this.getPost({ params })

• If you have an action where you have data and params to set, just do it like this:

// direct via store
const params = { id: 42 }
const data = { content: "foobar" }
this.$store.dispatch("actionName", { params, data })

// or with mapActions
this.actionName({ params, data })

Query params

If you want to use query params just set the queryParams property either in the constructor or the options from the add method. If you need it for just one action set it in the corresponding method. On the other hand, if you need it for all actions, set it in the constructor.

Please note that the method's queryParams property is more specific than the constructor's. So if you set queryParams in a method's options it will override the queryParams value of the constructor option!

Params will also be appended to the URL if you set a paramsSerializer function in the requestConfig property of the add method or if you pass an axios instance with set paramsSerializer function in the Resource constructor.

Add additional state, actions and mutations to the store

As mentioned before, vuex-rest-api is just creating a regular store object. So you can add arbitrary actions, mutations and state properties to the store as written in the Vuex documentation:

// resource creation hidden for the sake of brevity

// create the store
posts = postsResource.getStore()

// add a simple counter to the store
posts.state.counter = 0
posts.mutations.increment = state => {
  state.counter++
}
posts.actions.increment = context => {
  context.commit("increment")
}

Usage with websanova/vue-auth

If you want to use this little helper with vue-auth you don't have to do anything. It will just work due to the fact that vue-auth uses the global axios instance. Don't pass any axios instance to Vapi and it will work.

Check error and loading state of requests

vuex-rest-api sets for every property set in the add() method two different states:

• state.pending.<propertyName> (true when loading, otherwise false)
• state.error.<propertyName> (null if there's no error, otherwise it contains the error object)

This is really handy if you want to show a loading hint for specific requests or an error message:

<template>
  <div>
    <ul>
      <li v-for="post in posts">{{post}}</li>
    </ul>
    <p v-if="pending.posts">loading posts...</p>
    <p v-if="error.posts">loading failed</p>
  </div>
</template>

<script>
import { mapState, mapActions } from 'vuex'

export default {
  created() {
    this.getPosts()
  },

  // make states available
  computed: mapState({
    posts: state => state.posts.posts,
    pending: state => state.pending,
    error: state => state.error
  }),
  methods: {
    ...mapActions([
      "getPosts"
    ])
  }
}
</script>

Changelog

see CHANGELOG.md