@hzzt/react-activation
v0.0.4
Published
<KeepAlive /> for React like <keep-alive /> in vue
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React Activation
English | 中文说明
Implementation of the <keep-alive />
function in Vue
For React
More stable <KeepAlive />
function with babel
pre-compilation
More examples
Compatibility
React v17+ (beta)
React v16+
Preact v10+
Compatible with SSR
Install
yarn add react-activation
# or
npm install react-activation
Usage
1. Add react-activation/babel
plugins in .babelrc
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
.
{
"plugins": [
"react-activation/babel"
]
}
2. In your business code, place the <AliveScope>
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 <AliveScope>
inside <Router>
or <Provider>
// entry.js
import React from 'react'
import ReactDOM from 'react-dom'
import { AliveScope } from 'react-activation'
import Test from './Test'
ReactDOM.render(
<AliveScope>
<Test />
</AliveScope>,
document.getElementById('root')
)
3. Wrap the components that need to keep states with <KeepAlive>
Like the <Counter>
component in the example
// Test.js
import React, { useState } from 'react'
import KeepAlive from 'react-activation'
function Counter() {
const [count, setCount] = useState(0)
return (
<div>
<p>count: {count}</p>
<button onClick={() => setCount(count => count + 1)}>Add</button>
</div>
)
}
function Test() {
const [show, setShow] = useState(true)
return (
<div>
<button onClick={() => setShow(show => !show)}>Toggle</button>
{show && (
<KeepAlive>
<Counter />
</KeepAlive>
)}
</div>
)
}
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
...
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 && (
<KeepAlive>
<TestClass />
<TestFunction />
</KeepAlive>
)}
)
}
...
Save Scroll Position (true
by default)
<KeepAlive />
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 <KeepAlive />
to do this thing, set saveScrollPosition
prop to false
<KeepAlive saveScrollPosition={false} />
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
<KeepAlive saveScrollPosition="screen" />
Multiple Cache
Under the same parent node, <KeepAlive>
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.
<Route
path="/item/:id"
render={props => (
<KeepAlive>
<Item {...props} />
</KeepAlive>
)}
/>
Similar scenarios, you can use the id
attribute of <KeepAlive>
to implement multiple caches according to specific conditions.
<Route
path="/item/:id"
render={props => (
<KeepAlive id={props.match.params.id}>
<Item {...props} />
</KeepAlive>
)}
/>
Cache Control
Automatic control cache
Add the when
attribute to the <KeepAlive />
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
<KeepAlive when={false}>
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 <KeepAlive>
, including all <KeepAlive>
nested in <KeepAlive>
.
// For example:
// The following indicates that it is not cached when uninstalling
// And uninstalls all nested `<KeepAlive>`
<KeepAlive when={[false, true]}>
...
<KeepAlive>
...
<KeepAlive>...</KeepAlive>
...
</KeepAlive>
...
</KeepAlive>
When the when
type is Function
The return value is the above Boolean
or Array
, which takes effect as described above.
Manually control the cache
Add the
name
attribute to the<KeepAlive>
tag that needs to control the cache.Get control functions using
withAliveScope
oruseAliveController
drop(name)
Unload the
<KeepAlive>
node in cache state by name. The name can be of typeString
orRegExp
. Note that only the first layer of content that hits<KeepAlive>
is unloaded and will not be uninstalled in<KeepAlive>
. Would not unload nested<KeepAlive>
dropScope(name)
Unloads the
<KeepAlive>
node in cache state by name. The name optional type isString
orRegExp
, which will unload all content of<KeepAlive>
, including all<KeepAlive>
nested in<KeepAlive>
.clear()
will clear all
<KeepAlive>
in the cachegetCachingNodes()
Get all the nodes in the cache
...
import KeepAlive, { withAliveScope, useAliveController } from 'react-activation'
...
<KeepAlive name="Test">
...
<KeepAlive>
...
<KeepAlive>
...
</KeepAlive>
...
</KeepAlive>
...
</KeepAlive>
...
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 <KeepAlive />
to <AliveScope />
and render it with <Keeper />
After rendering <Keeper />
, the content is transferred to <KeepAlive />
through DOM
operation.
Since <Keeper />
will not be uninstalled, caching can be implemented.
Breaking Change
<KeepAlive />
needs to pass children to<AliveScope />
, so the rendering of the real content will be slower than the normal situationWill have a certain impact on the function of strictly relying on the lifecycle order, such as getting the value of
ref
incomponentDidMount
, as followsclass Test extends Component { componentDidMount() { console.log(this.outside) // will log <div /> instance console.log(this.inside) // will log undefined } render() { return ( <div> <div ref={ref => { this.outside = ref }} > Outside KeepAlive </div> <KeepAlive> <div ref={ref => { this.inside = ref }} > Inside KeepAlive </div> </KeepAlive> </div> ) } }
The above error in
ClassComponent
can be fixed by using thewithActivation
high-level componentFunctionComponent
currently has no processing method, you can usesetTimeout
ornextTick
to delay ref getting behavior@withActivation class Test extends Component { componentDidMount() { console.log(this.outside) // will log <div /> instance console.log(this.inside) // will log <div /> instance } render() { return ( <div> <div ref={ref => { this.outside = ref }} > Outside KeepAlive </div> <KeepAlive> <div ref={ref => { this.inside = ref }} > Inside KeepAlive </div> </KeepAlive> </div> ) } }
Destructive impact on
Context
, need to be manually fixedProblem reference: https://github.com/StructureBuilder/react-keep-alive/issues/36
<Provider value={1}> {show && ( <KeepAlive> <Consumer> {( context // Since the rendering level is broken, the context cannot be obtained here. ) => <Test contextValue={context} />} </Consumer> </KeepAlive> )} <button onClick={toggle}>toggle</button> </Provider>
Choose a repair method
Create
Context
usingcreateContext
exported fromreact-activation
Fix the affected
Context
withfixContext
exported fromreact-activation
... import { createContext } from 'react-activation' const { Provider, Consumer } = createContext() ... // or ... import { createContext } from 'react' import { fixContext } from 'react-activation' const Context = createContext() const { Provider, Consumer } = Context fixContext(Context) ...
Affects the functionality that depends on the level of the React component, as follows
- [x] Fix
withRouter/hooks
of react-router - [x] ~~Error Boundaries~~ (Fixed)
- [x] ~~React.Suspense & React.lazy~~ (Fixed)
- [ ] React Synthetic Event Bubbling Failure
- [ ] Other undiscovered features
- [x] Fix