React Activation


English | 中文说明

Implementation of the function in Vue For React

---

More stable function with babel pre-compilation

Online Demo

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More examples

- Closable tabs with react-router
- Closable tabs with umi
- Using Animation with react-router

---

Compatibility

- React v17+ (beta)

- React v16+

- Preact v10+

- Compatible with SSR

---

Install

``bash
yarn add react-activation


or

#### 1. Add react-activation/babel plugins in .babelrc

Why is it needed?

The plugin adds a _nk attribute to each JSX element during compilation to help the react-activation runtime generate an unique identifier by render location base on react-node-key.

`javascript
{
"plugins": [
"react-activation/babel"
]
}
`

#### 2. In your business code, place the outer layer at a location that will not be unmounted, usually at the application entrance

Note: When used with react-router or react-redux, you need to place inside or

`javascript
// entry.js

import React from 'react'
import ReactDOM from 'react-dom'
import { AliveScope } from 'react-activation'

import Test from './Test'

ReactDOM.render(


,
document.getElementById('root')
)
`

#### 3. Wrap the components that need to keep states with

Like the component in the example

`javascript
// Test.js

import React, { useState } from 'react'
import KeepAlive from 'react-activation'

function Counter() {
const [count, setCount] = useState(0)

return (


export default Test
`

---

Lifecycle

ClassComponent works with withActivation decorator

Use componentDidActivate and componentWillUnactivate to correspond to the two states of "activate" and "unactivate" respectively.

FunctionComponent uses the useActivate and useUnactivate hooks respectively

`javascript
...
import KeepAlive, { useActivate, useUnactivate, withActivation } from 'react-activation'

@withActivation
class TestClass extends Component {
...
componentDidActivate() {
console.log('TestClass: componentDidActivate')
}

componentWillUnactivate() {
console.log('TestClass: componentWillUnactivate')
}
...
}
...
function TestFunction() {
useActivate(() => {
console.log('TestFunction: didActivate')
})

useUnactivate(() => {
console.log('TestFunction: willUnactivate')
})
...
}
...
function App() {
...
return (
{show && (




)}
)
}
...
`

---

Save Scroll Position (true by default)

would try to detect scrollable nodes in its children, then, save their scroll position automaticlly before componentWillUnactivate and restore saving position after componentDidActivate

If you don't want to do this thing, set saveScrollPosition prop to false

`javascript

`

If your components share screen scroll container, document.body or document.documentElement, set saveScrollPosition prop to "screen" can save sharing screen container's scroll position before componentWillUnactivate

`javascript

`

---

Multiple Cache

Under the same parent node, in the same location will use the same cache by default.

For example, with the following parameter routing scenario, the /item route will be rendered differently by id, but only the same cache can be kept.

`javascript
path="/item/:id"
render={props => (



)}
/>
`

Similar scenarios, you can use the id attribute of to implement multiple caches according to specific conditions.

`javascript
path="/item/:id"
render={props => (



)}
/>
`

---

Cache Control

$3

Add the when attribute to the tag that needs to control the cache. The value is as follows

#### When the when type is Boolean

- true: Cache after uninstallation
- false: Not cached after uninstallation

`javascript

`

#### When the when type is Array

The 1th parameter indicates whether it needs to be cached at the time of uninstallation.

The 2th parameter indicates whether to unload all cache contents of , including all nested in .

`javascript
// For example:
// The following indicates that it is not cached when uninstalling
// And uninstalls all nested

...

...
...
...

...

`

#### When the when type is Function

The return value is the above Boolean or Array, which takes effect as described above.

$3

1. Add the name attribute to the tag that needs to control the cache.

2. Get control functions using withAliveScope or useAliveController

- drop(name)

Unload the node in cache state by name. The name can be of type String or RegExp. Note that only the first layer of content that hits is unloaded and will not be uninstalled in . Would not unload nested

- dropScope(name)

Unloads the node in cache state by name. The name optional type is String or RegExp, which will unload all content of , including all nested in .

- clear()

will clear all in the cache

- getCachingNodes()

Get all the nodes in the cache

`javascript
...
import KeepAlive, { withAliveScope, useAliveController } from 'react-activation'
...

...

...

...

...

...

...
function App() {
const { drop, dropScope, clear, getCachingNodes } = useAliveController()

useEffect(() => {
drop('Test')
// or
drop(/Test/)
// or
dropScope('Test')

clear()
})

return (
...
)
}
// or
@withAliveScope
class App extends Component {
render() {
const { drop, dropScope, clear, getCachingNodes } = this.props

return (
...
)
}
}
...
`

---

Principle

Pass the children attribute of to and render it with

After rendering , the content is transferred to through DOM operation.

Since will not be uninstalled, caching can be implemented.

Simplest Implementation Demo

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Breaking Change

1. needs to pass children to , so the rendering of the real content will be slower than the normal situation

Will have a certain impact on the function of strictly relying on the lifecycle order, such as getting the value of ref in componentDidMount, as follows

`javascript
class Test extends Component {
componentDidMount() {
console.log(this.outside) // will log