halux

HAL middleware for Redux which uses HalCrawler under the hood. If your state matches the HAL conventions described in the above Repo, you can use this middleware to load nested HAL resources easily. The authors of both modules teamed up and discussed the API and application flow together.

Usage

To use this module, please install it's peer dependency HalCrawler.

$ npm install -S hal-crawler

Setup your HAL config and then install this module using:

$ npm install -S halux

For the following examples I use the config generated by Hal-Crawler.

To see a working example check out Hal-Crawler examples: [HalCrawlerExample]

create a Halux action

We provide a helper method for you to create a Halux action. Although it's not necessary, we highly recommend using it.

The interface for this action is:
(haluxObject: {
    schema: Schema, // a Hal-crawler Schema
    link?: string, // url to resource
    identifiers?: {
        [index: string]: any, // an object of identifiers to identify the different Resources
    },
    body?: any; // if body is set, then a post will be executed using the body
    into?: Schema; // defines in which schema the result should be stored
    overwriteStore?: boolean; // ignore state in store and always refetch resource, default: false
    handlers?: { // handler to be called on a particular event. Can be a redux-action or a regular function
        successHandler?: (reduxStore: any, haluxState: any, createdResource: Resource) => any,
        pendingHandler?: (reduxStore: any) => any,
        errorHandler?: (reduxStore: any, error: any) => any,
    }
    config?: any; // pass custom configuration object, nested calls will receive the same config object
}): HaluxActionI

Note that only identifiers or link should be set, not both.

You can use the method like this:

import { createHaluxAction } from 'halux';

const fetchRoot = () => createHaluxAction({
    schema: root,
    identifiers: undefined
});

const fetchAdmins = ({ clientId: id} ) => createHaluxAction({
    schema: admins,
    identifiers: {
        id,
    },
    handlers: {
        errorHandler: (reduxStore, error) => console.log(error.toString())
    }
});

nestHaluxActions

Because each Schema must be inside the root schema, nesting actions is need. You can use the provided nestHaluxActions method to do so. It is possible to nest data as many layers deep as you need to, but only one level per method called

The interface is:

const nested = nestHaluxActions(
   () => createHaluxAction({...}),
   () => createHaluxAction({...})
);

nested({}, {}); // one object per method

Example using the above setup:

const nestedAdmins = (client) => nestHaluxActions(fetchRoot, fetchAdmins)({}, client);

// now you would dispatch this action like this:
dispatch(nestedAdmins({ clientId: 1 }))

Reducer

This library provides its own reducer which you should insert into your state. The reducer knows how to handle the actions created by the middleware and updates the store accordingly. It is not recommended to use a custom reducer for managing those actions as it's considered an internal feature and may change. To use the reducer import haluxReducer from the middleware and combine it into your store.

Example:

import { combineReducers } from 'redux';
import { haluxReducer } from 'halux';

export const store = combineReducers({
    app: {}, // your app state
    data: combineReducers({
        halux: haluxReducer,
        somethingOther: {},
    })
})

Middleware

Finally you have to add the middleware. There is a helper method to create the middleware which you must use. It accepts the hal-crawler config as the first parameter and the location of the halux store inside the store as a second parameter. The location must be a string and may be something like this: 'data.halux'. It's default value is data.halux. The helper function returns the middleware which can be passed to the createStore method.

import { createHalux } from 'halux';
import { createStore, applyMiddleware } from 'redux';

const haluxMiddleware = createHalux(config, 'data.halux');

const store = createStore(
  reducers,
  undefined,
  applyMiddleware(haluxMiddleware)
)

 [HalCrawlerExample]: https://github.com/StuckiSimon/HalCrawler/tree/master/example/halux-integration