Example: Reddit API

Last updated 3 months ago

This is the complete source code of the Reddit headline fetching example we built during the advanced tutorial.

Entry Point

index.js

import 'babel-polyfill'
import React from 'react'
import { render } from 'react-dom'
import Root from './containers/Root'
render(
<Root />,
document.getElementById('root')
)

Action Creators and Constants

actions.js

import fetch from 'cross-fetch'
export const REQUEST_POSTS = 'REQUEST_POSTS'
export const RECEIVE_POSTS = 'RECEIVE_POSTS'
export const SELECT_SUBREDDIT = 'SELECT_SUBREDDIT'
export const INVALIDATE_SUBREDDIT = 'INVALIDATE_SUBREDDIT'
export function selectSubreddit(subreddit) {
return {
type: SELECT_SUBREDDIT,
subreddit
}
}
export function invalidateSubreddit(subreddit) {
return {
type: INVALIDATE_SUBREDDIT,
subreddit
}
}
function requestPosts(subreddit) {
return {
type: REQUEST_POSTS,
subreddit
}
}
function receivePosts(subreddit, json) {
return {
type: RECEIVE_POSTS,
subreddit,
posts: json.data.children.map(child => child.data),
receivedAt: Date.now()
}
}
function fetchPosts(subreddit) {
return dispatch => {
dispatch(requestPosts(subreddit))
return fetch(`https://www.reddit.com/r/${subreddit}.json`)
.then(response => response.json())
.then(json => dispatch(receivePosts(subreddit, json)))
}
}
function shouldFetchPosts(state, subreddit) {
const posts = state.postsBySubreddit[subreddit]
if (!posts) {
return true
} else if (posts.isFetching) {
return false
} else {
return posts.didInvalidate
}
}
export function fetchPostsIfNeeded(subreddit) {
return (dispatch, getState) => {
if (shouldFetchPosts(getState(), subreddit)) {
return dispatch(fetchPosts(subreddit))
}
}
}

Reducers

reducers.js

import { combineReducers } from 'redux'
import {
SELECT_SUBREDDIT,
INVALIDATE_SUBREDDIT,
REQUEST_POSTS,
RECEIVE_POSTS
} from './actions'
function selectedSubreddit(state = 'reactjs', action) {
switch (action.type) {
case SELECT_SUBREDDIT:
return action.subreddit
default:
return state
}
}
function posts(
state = {
isFetching: false,
didInvalidate: false,
items: []
},
action
) {
switch (action.type) {
case INVALIDATE_SUBREDDIT:
return Object.assign({}, state, {
didInvalidate: true
})
case REQUEST_POSTS:
return Object.assign({}, state, {
isFetching: true,
didInvalidate: false
})
case RECEIVE_POSTS:
return Object.assign({}, state, {
isFetching: false,
didInvalidate: false,
items: action.posts,
lastUpdated: action.receivedAt
})
default:
return state
}
}
function postsBySubreddit(state = {}, action) {
switch (action.type) {
case INVALIDATE_SUBREDDIT:
case RECEIVE_POSTS:
case REQUEST_POSTS:
return Object.assign({}, state, {
[action.subreddit]: posts(state[action.subreddit], action)
})
default:
return state
}
}
const rootReducer = combineReducers({
postsBySubreddit,
selectedSubreddit
})
export default rootReducer

Store

configureStore.js

import { createStore, applyMiddleware } from 'redux'
import thunkMiddleware from 'redux-thunk'
import { createLogger } from 'redux-logger'
import rootReducer from './reducers'
const loggerMiddleware = createLogger()
export default function configureStore(preloadedState) {
return createStore(
rootReducer,
preloadedState,
applyMiddleware(
thunkMiddleware,
loggerMiddleware
)
)
}

Container Components

containers/Root.js

import React, { Component } from 'react'
import { Provider } from 'react-redux'
import configureStore from '../configureStore'
import AsyncApp from './AsyncApp'
const store = configureStore()
export default class Root extends Component {
render() {
return (
<Provider store={store}>
<AsyncApp />
</Provider>
)
}
}

containers/AsyncApp.js

import React, { Component } from 'react'
import PropTypes from 'prop-types'
import { connect } from 'react-redux'
import {
selectSubreddit,
fetchPostsIfNeeded,
invalidateSubreddit
} from '../actions'
import Picker from '../components/Picker'
import Posts from '../components/Posts'
class AsyncApp extends Component {
constructor(props) {
super(props)
this.handleChange = this.handleChange.bind(this)
this.handleRefreshClick = this.handleRefreshClick.bind(this)
}
componentDidMount() {
const { dispatch, selectedSubreddit } = this.props
dispatch(fetchPostsIfNeeded(selectedSubreddit))
}
componentDidUpdate(prevProps) {
if (this.props.selectedSubreddit !== prevProps.selectedSubreddit) {
const { dispatch, selectedSubreddit } = this.props
dispatch(fetchPostsIfNeeded(selectedSubreddit))
}
}
handleChange(nextSubreddit) {
this.props.dispatch(selectSubreddit(nextSubreddit))
this.props.dispatch(fetchPostsIfNeeded(nextSubreddit))
}
handleRefreshClick(e) {
e.preventDefault()
const { dispatch, selectedSubreddit } = this.props
dispatch(invalidateSubreddit(selectedSubreddit))
dispatch(fetchPostsIfNeeded(selectedSubreddit))
}
render() {
const { selectedSubreddit, posts, isFetching, lastUpdated } = this.props
return (
<div>
<Picker
value={selectedSubreddit}
onChange={this.handleChange}
options={['reactjs', 'frontend']}
/>
<p>
{lastUpdated &&
<span>
Last updated at {new Date(lastUpdated).toLocaleTimeString()}.
{' '}
</span>}
{!isFetching &&
<button onClick={this.handleRefreshClick}>
Refresh
</button>}
</p>
{isFetching && posts.length === 0 && <h2>Loading...</h2>}
{!isFetching && posts.length === 0 && <h2>Empty.</h2>}
{posts.length > 0 &&
<div style={{ opacity: isFetching ? 0.5 : 1 }}>
<Posts posts={posts} />
</div>}
</div>
)
}
}
AsyncApp.propTypes = {
selectedSubreddit: PropTypes.string.isRequired,
posts: PropTypes.array.isRequired,
isFetching: PropTypes.bool.isRequired,
lastUpdated: PropTypes.number,
dispatch: PropTypes.func.isRequired
}
function mapStateToProps(state) {
const { selectedSubreddit, postsBySubreddit } = state
const {
isFetching,
lastUpdated,
items: posts
} = postsBySubreddit[selectedSubreddit] || {
isFetching: true,
items: []
}
return {
selectedSubreddit,
posts,
isFetching,
lastUpdated
}
}
export default connect(mapStateToProps)(AsyncApp)

Presentational Components

components/Picker.js

import React, { Component } from 'react'
import PropTypes from 'prop-types'
export default class Picker extends Component {
render() {
const { value, onChange, options } = this.props
return (
<span>
<h1>{value}</h1>
<select onChange={e => onChange(e.target.value)} value={value}>
{options.map(option => (
<option value={option} key={option}>
{option}
</option>
))}
</select>
</span>
)
}
}
Picker.propTypes = {
options: PropTypes.arrayOf(PropTypes.string.isRequired).isRequired,
value: PropTypes.string.isRequired,
onChange: PropTypes.func.isRequired
}

components/Posts.js

import React, { Component } from 'react'
import PropTypes from 'prop-types'
export default class Posts extends Component {
render() {
return (
<ul>
{this.props.posts.map((post, i) => <li key={i}>{post.title}</li>)}
</ul>
)
}
}
Posts.propTypes = {
posts: PropTypes.array.isRequired
}