redux-query

redux-query

redux-query is a library for querying and managing network state in React/Redux applications. Brought to you by Amplitude.

With redux-query you can:

• Declare your network dependencies right next to your React components. Data is requested automatically when components mount. When components update and unmount, in-flight requests are automatically cancelled.
• Trigger server-side changes (mutations) by dispatching regular Redux actions.
• Have a consistent, minimal-boilerplate interface for all network-related state.
• Transform and normalize data to avoid duplicate state.
• Perform optimistic updates.
• Use with other Redux middleware libraries like redux-thunk and redux-saga.
• Debug network state and actions with Redux dev tools like redux-logger.

Getting Started

Install redux-query via npm:

$ npm install --save redux-query

Add the entitiesReducer and queriesReducer to your combined reducer.

Include the queryMiddleware in your store's applyMiddleware call. queryMiddleware requires two arguments: a selector (or function) that returns entities state, and a function for the queries state.

For example:

import { applyMiddleware, createStore, combineReducers } from 'redux';
import { entitiesReducer, queriesReducer, queryMiddleware } from 'redux-query';
import createLogger from 'redux-logger';

export const getQueries = (state) => state.queries;
export const getEntities = (state) => state.entities;

const reducer = combineReducers({
  entities: entitiesReducer,
  queries: queriesReducer,
});

const logger = createLogger();
const store = createStore(
  reducer,
  applyMiddleware(queryMiddleware(getQueries, getEntities), logger)
);

Interactive Demos

There are several interactive demos at https://amplitude.github.io/redux-query:

• Hello World
• Mounting and Unmounting
• Updating from Props
• Mutations
• Usage with redux-saga
• Hacker News

After making code changes, click the "Run" button above the code editor to view your changes.

Most of these demos use a mock server, which lets you also experiment with different server logic. Click on the "Mock Server" tab above the code editor to view and modify the mock server logic. In addition, you can view the log of redux actions and states by clicking on the "Redux Log" tab.

Dependencies

All dependencies are listed in package.json. Redux and React are peer dependencies. HTTP requests are made using superagent.

Usage and API

Requests and mutations

There are two types of queries with redux-query: "requests" and "mutations". Requests are for reading values from HTTP endpoints. Mutations are for HTTP endpoints that change network state – the "C", "U", and "D" in "CRUD".

Requests can be triggered from the connectRequest higher-order component or a requestAsync action. Mutations are triggered by dispatching a mutateAsync action.

By default, requests are GETs and mutations are POSTS.

Query configs

Query configs are objects used to describe how redux-query should handle the request or mutation. Query config options differ slightly between requests and mutations

Request query config options

Name	Type	Required?	Description
url	string	yes	The URL for the HTTP request.
transform	function		A function that transforms the response data to an entities object where keys are entity IDs and values are entity data. Can be used to normalize data.
update	object	yes	An object where keys are entity IDs and values are "update functions" (see below).
body	object		The request body. For GETs, this object is stringified and appended to the URL as query params.
force	boolean		A flag to indicate that the request should be performed even if a previous query with the same query key succeeded.
queryKey	string		The identifier used to identify the query metadata in the queries reducer. If unprovided, the url and body fields are serialized to generate the query key.
meta	object		Various metadata for the query. Can be used to update other reducers when queries succeed or fail.
options	object		Options for the request. Set options.method to change the HTTP method, options.headers to set any headers and options.credentials = 'include' for CORS.

Mutation query config options

Name	Type	Required?	Description
url	string	yes	The URL for the HTTP request.
transform	function		A function that transforms the response data to an entities object where keys are entity IDs and values are entity data. Can be used to normalize data.
update	object	yes	An object where keys are entity IDs and values are "update functions" (see below).
optimisticUpdate	object		An object where keys are entity IDs and values are "optimisticUpdate functions" (see below). Used to update entities immediately when the mutation starts.
rollback	object		An object where keys are entity IDs and values are "rollback functions" (see below). Used to reverse the effects of optimisticUpdate when the mutation fails. If not provided, the entity will simply be reverted to its value before the optimisticUpdate was performed.
body	object		The HTTP request body. For GETs, this object is stringified and appended to the URL as query params.
queryKey	string		The identifier used to identify the query metadata in the queries reducer. If unprovided, the url and body fields are serialized to generate the query key.
meta	object		Various metadata for the query. Can be used to update other reducers when queries succeed or fail.
options	object		Options for the request. Set options.method to change the HTTP method, options.headers to set any headers and options.credentials = 'include' for CORS.

transform functions

transform functions let you process and normalize response data before it is passed to the update step. They have the following signature:

(responseJson: ?Object, responseText: string) => { [key: string]: any }

If your data is normalized on the server, you may not need to use this function.

update functions

update functions are responsible for reconciling response data with the existing entities reducer data for the given entity ID. They have the following signature:

(prevValue: any, transformedValue: any) => any

The prevValue is the whatever value is selected from the entities reducer for the respective entity ID. The returned value from this function will become the new value for the entity ID in the entities reducer.

optimisticUpdate functions

optimisticUpdate functions are just like update functions except they only pass the prevValue:

(prevValue: any) => any

rollback functions

rollback functions are used to reverse the effect of optimisticUpdates when the mutation fails. They are provided two parameters: the state of the entity before the optimistic update and the current state of the entity:

(initialValue: any, currentValue: any) => any

Specifying rollback functions are not required. However, it is recommended for entities that are partially updated (e.g. an object collection of items keyed by IDs). The default rollback behavior is equivalent to the following:

(initialValue, currentValue) => initialValue

connectRequest

Use the connectRequest higher-order component to declare network dependencies for a React component.

connectRequest takes a function, mapPropsToConfigs, that transforms the component props to a request query config or an array of request query configs. You can think of mapPropsToConfigs similarly to react-redux's mapStateToProps and mapDispatchToProps.

On mount, every query config returned from mapPropsToConfigs will result in a dispatched requestAsync Redux action. When the props update, mapPropsToConfigs is called again. All pending requests that were removed will be cancelled and all new configs will result in a dispatched requestAsync Redux action. On unmount, all pending requests will be cancelled.

Please note, just because a requestAsync Redux action was dispatched, does not mean that an actual network request will occur. Requests that were previously successful will not result in another network request, unless the corresponding query config has force set to true.

99% of the time you'll be using react-redux's connect at the same time when you are using connectRequest. You might find using redux's compose function makes this a bit more elegant.

Example usage:

import { compose } from 'redux';
import { connectRequest } from 'redux-query';
import { connect } from 'react-redux';

class Dashboard extends Component {
  ...
}

const mapStateToProps = (state, props) => ({
  dashboard: getDashboard(state, props),
});

const mapPropsToConfigs = props => [
  {
    url: `/api/dashboard/${props.dashboardId}`,
    update: {
      chartsById: (prevCharts, dashboardCharts) => ({
        ...prevCharts,
        ...dashboardCharts,
      }),
      dashboardsById: (prevDashboards, dashboards) => ({
        ...prevDashboards,
        ...dashboards,
      }),
    },
  }
];

export default compose(
  connect(mapStateToProps),
  connectRequest(mapPropsToConfigs)
)(Dashboard);

connectRequest passes an extra prop to the child component: forceRequest. Calling this function will cause the request(s) to be made again. This may be useful for polling or creating an interface to trigger refreshes.

mutateAsync

Dispatch mutateAsync Redux actions to trigger mutations. mutateAsync takes a mutation query config as its only argument. Example usage with a react-redux-connected component:

// src/queries/dashboard.js

export const createUpdateDashboardQuery = (dashboardId, newName) => ({
  url: `/api/${dashboardId}/update`,
  body: {
    name: newName,
  },
  update: {
    dashboardsById: (prevDashboardsById, newDashboardsById) => ({
      ...prevDashboardsById,
      ...newDashboardsById,
    }),
  },
});

// src/actions/dashboard.js

import { mutateAsync } from 'redux-query';
import { createUpdateDashboardQuery } from '../queries/dashboard';

export const updateDashboard = (dashboardId, newName) => {
  return mutateAsync(createUpdateDashboardQuery(dashboardId, newName));
};

// src/selectors/dashboard.js

export const getDashboard = (state, { dashboardId }) => {
  if (state.entities.dashboardsById) {
    return state.entities.dashboardsById[dashboardId];
  } else {
    return null;
  }
};

// src/components/Dashboard.jsx

import { connect } from 'react-redux';

import { updateDashboard } from '../actions/dashboard';
import { getDashboard } from '../selectors/dashboard';

class Dashboard extends Component {
  ...
}

const mapStateToProps = (state, props) => {
  return {
    dashboard: getDashboard(state, props),
  };
};

const mapDispatchToProps = (dispatch, props) => {
  return {
    changeName: (newName) => {
      dispatch(updateDashboard(props.dashboardId, newName));
    },
  };
};

export default connect(mapStateToProps, mapDispatchToProps)(Dashboard);

When dispatching a mutateAsync action, you can Promise-chain on the returned value from dispatch:

const mapDispatchToProps = (dispatch, props) => {
  return {
    changeName: (newName) => {
      dispatch(updateDashboard(props.dashboardId, newName)).then((result) => {
        if (result.status !== 200) {
          dispatch(showUpdateDashboardFailedNotification(props.dashboardId));
        }
      });
    },
  };
};

The result of the promise returned by mutateAsync will be the following object:

Name	Type	Description
status	number	HTTP status code.
body	object or null	Parsed response body.
text	string	Unparsed response body string.
duration	number	The total duration from the start of the query to receiving the full response.

When the mutation succeeds, it will also include the following fields:

Name	Type	Description
transformed	any	Result from the transform function. Will be identical to body if transform is unprovided in the query config.
entities	object	The new, updated entities that have been affected by the query.

requestAsync

Similarly to how mutations are triggered by dispatching mutateAsync actions, you can trigger requests by dispatching requestAsync actions with a request query config.

You can also Promise-chain on dispatched requestAsync actions, but a Promise will only be returned if redux-query determines it will make a network request. For example, if the query config does not have force set to true and a previous request with the same query key previously succeeded, then a Promise will not be returned. So be sure to always check that the returned value from a dispatched requestAsync is a Promise before interacting with it.

Queries selectors

redux-query provides some useful selectors for reading from the queries reducer state:

Selector Name	Return Type	Description
isFinished	?boolean	Returns true if the query was resolved or cancelled.
isPending	?boolean	Returns true if the query is in-flight – not resolved and not cancelled.
status	?number	Response HTTP status code.
lastUpdated	?number	Time at which the query was resolved.
queryCount	?number	Number of times a query was started with the same query key.

All of the query selectors have the following signature:

(queriesReducerState, queryConfig) => mixed

Errors reducer and selectors

redux-query provides another reducer for applications that want to track response body, text, and headers in redux state. Unlike the entities and queries reducers, errorsReducer is totally optional. If you include this reducer in your application's combined reducer, all responses from requests and mutations with non-2xx status codes will be recorded in this state.

Note: If your application has many queries that could potentially error and is used for long periods of time, you should avoid using this reducer as it could potentially accumulate a lot of memory usage. You can alternatively build your own reducer to track a subset of queries, or rely on the promise interface to handle error responses in an ad-hoc manor.

You can query from this state using the provided errorSelectors:

Selector Name	Return Type	Description
responseBody	?Object	Parsed response body (if query failed).
responseText	?string	Unparsed response body string (if query failed).
responseHeaders	?Object	Response headers (if query failed).

All of the query selectors have the following signature:

(errorsReducerState, queryConfig) => mixed

Custom network interfaces

By default, redux-query makes XHR requests using the superagent library. If you'd rather use a different library for making requests, you can use redux-query's queryMiddlewareAdvanced middleware.

If you use a custom network interface and want to avoid including superagent in your bundle, change all of your imports from redux-query to redux-query/advanced.

Note: The default queryMiddleware exported from the main redux-query entry point is simply a superagent network interface bound to queryMiddlewareAdvanced.

Network interfaces have the following interface:

type NetworkInterface = (
  url: string,
  method: 'GET' | 'POST' | 'PUT' | 'PATCH' | 'DELETE',
  config?: { body?: string | Object, headers?: Object, credentials?: 'omit' | 'include' } = {},
) => NetworkHandler;

type NetworkHandler = {
  execute: (callback: (err: any, resStatus: number, resBody: ?Object, resText: string, resHeaders: Object) => void) => void,
  abort: () => void,
};

Example queryMiddlewareAdvanced usage:

import { applyMiddleware, createStore, combineReducers } from 'redux';
import { entitiesReducer, queriesReducer, queryMiddlewareAdvanced } from 'redux-query/advanced';

// A function that takes a url, method, and other options. This function should return an object
// with two required properties: execute and abort.
import myNetworkInterface from './network-interface';

export const getQueries = (state) => state.queries;
export const getEntities = (state) => state.entities;

const reducer = combineReducers({
  entities: entitiesReducer,
  queries: queriesReducer,
});

const store = createStore(
  reducer,
  applyMiddleware(queryMiddlewareAdvanced(myNetworkInterface)(getQueries, getEntities))
);

Example

A fork of the redux Async example is included. To run, first build the package:

$ yarn install
$ yarn run build

Then you can run the example:

$ cd examples/async
$ yarn install
$ yarn run start

Changelog

2.3.1

• Support redux v4 (karevn #103)