CacheRoute

English | 中文说明

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

Online Demo

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

React v15+

React-Router v4+

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Problem Scenarios

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

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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/remix-run/react-router/blob/v5.3.4/packages/react-router/modules/Route.js#L46-L61

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Install

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

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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

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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/

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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.

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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

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Lifecycles

Hooks

use useDidCache and useDidRecover to inject customer Lifecycle didCache and didRecover

import { useDidCache, useDidRecover } from 'react-router-cache-route'

export default function List() {

  useDidCache(() => {
    console.log('List cached 1')
  })

  // support multiple effect
  useDidCache(() => {
    console.log('List cached 2')
  })

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

  return (
    // ...
  )
}

Class Component

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 (
      // ...
    )
  }
}

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Drop cache

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')
...

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Clear cache

You can clear cache with clearCache function.

import { clearCache } from 'react-router-cache-route'

clearCache()