CacheRoute

English | 中文说明

Route with cache for react-router like keep-alive in Vue.

If you want <KeepAlive /> only, try react-activation

React v15+

React-Router v4+

Problem

Using Route, component can not be cached while going forward or back which lead to losing data and interaction

Reason & Solution

Component would be unmounted when Route was unmatched

After reading source code of Route we found that using children prop as a function could help to control rendering behavior.

Hiding instead of Removing would fix this issue.

https://github.com/ReactTraining/react-router/blob/master/packages/react-router/modules/Route.js#L41-L63

Install

npm install react-router-cache-route --save
# or
yarn add react-router-cache-route

Usage

Replace Route with CacheRoute

Replace Switch with CacheSwitch (Because Switch only keeps the first matching state route and unmount the others)

import React from 'react'
import { HashRouter as Router, Route } from 'react-router-dom'
import CacheRoute, { CacheSwitch } from 'react-router-cache-route'

import List from './views/List'
import Item from './views/Item'

const App = () => (
  <Router>
    <CacheSwitch>
      <CacheRoute exact path="/list" component={List} />
      <Route exact path="/item/:id" component={Item} />
      <Route render={() => <div>404 Not Found</div>} />
    </CacheSwitch>
  </Router>
)

export default App

CacheRoute props

| name | type | default | description | | ----------------------------- | --------------------- | -------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | when | String / Function | "forward" | Decide when to cache | | className | String | - | className prop for the wrapper component | | behavior | Function | cached => cached ? { style: { display: "none" }} : undefined | Return props effective on the wrapper component to control rendering behavior | | cacheKey | String / Function | - | For imperative control caching | | multiple (React v16.2+) | Boolean / Number | false | Allows different caches to be distinguished by dynamic routing parameters. When the value is a number, it indicates the maximum number of caches. When the maximum value is exceeded, the oldest updated cache will be cleared. | | unmount (UNSTABLE) | Boolean | false | Whether to unmount the real dom node after cached, to save performance (Will cause losing the scroll position after recovered, fixed with saveScrollPosition props) | | saveScrollPosition (UNSTABLE) | Boolean | false | Save scroll position |

CacheRoute is only a wrapper component that works based on the children property of Route, and does not affect the functionality of Route itself.

For the rest of the properties, please refer to https://reacttraining.com/react-router/

About when

The following values can be taken when the type is String

• [forward] Cache when forward behavior occurs, corresponding to the PUSH or REPLACE action in react-router
• [back] Cache when back behavior occurs, corresponding to the POP action in react-router
• [always] Always cache routes when leave, no matter forward or backward

When the type is Function, the component's props will be accepted as the first argument, return true/false to determine whether to cache.

CacheSwitch props

| name | type | default | description | | ----- | ---------- | ---------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | which | Function | element => element.type === CacheRoute | <CacheSwitch> only saves the first layer of nodes which type is CacheRoute by default, which prop is a function that would receive a instance of React Component, return true/false to decide if <CacheSwitch> need to save it, reference #55 |

Lifecycles

Component with CacheRoute will accept one prop named cacheLifecycles which contains two functions to inject customer Lifecycle didCache and didRecover

import React, { Component } from 'react'

export default class List extends Component {
  constructor(props) {
    super(props)

    props.cacheLifecycles.didCache(this.componentDidCache)
    props.cacheLifecycles.didRecover(this.componentDidRecover)
  }

  componentDidCache = () => {
    console.log('List cached')
  }

  componentDidRecover = () => {
    console.log('List recovered')
  }

  render() {
    return (
      // ...
    )
  }
}

Drop cache manually

You can manually control the cache with cacheKey prop and dropByCacheKey function.

import CacheRoute, { dropByCacheKey, getCachingKeys } from 'react-router-cache-route'

...
<CacheRoute ... cacheKey="MyComponent" />
...

console.log(getCachingKeys()) // will receive ['MyComponent'] if CacheRoute is cached which `cacheKey` prop is 'MyComponent'
...

dropByCacheKey('MyComponent')
...