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New to React. Just using create-react-app and Material UI, nothing else. Coming from an Angular background.
I cannot communicate from a sibling component to open the sidebar. I'm separating each part into their own files. I can get the open button in the Header to talk to the parent App, but cannot get the parent App to communicate with the child LeftSidebar.
import React, {Component} from 'react';
import AppBar from 'material-ui/AppBar';
import IconButton from 'material-ui/IconButton';
import NavigationMenu from 'material-ui/svg-icons/navigation/menu';
class Header extends Component {
openLeftBar = () => {
// calls parent method
this.props.onOpenLeftBar();
}
render() {
return (
<AppBar iconElementLeft={
<IconButton onClick={this.openLeftBar}>
<NavigationMenu />
</IconButton>
}
/>
);
}
}
export default Header;
import React, { Component } from 'react';
import darkBaseTheme from 'material-ui/styles/baseThemes/darkBaseTheme';
import MuiThemeProvider from 'material-ui/styles/MuiThemeProvider';
import getMuiTheme from 'material-ui/styles/getMuiTheme';
import RaisedButton from 'material-ui/RaisedButton';
import Drawer from 'material-ui/Drawer';
import MenuItem from 'material-ui/MenuItem';
// components
import Header from './Header/Header';
import Body from './Body/Body';
import Footer from './Footer/Footer';
import LeftSidebar from './LeftSidebar/LeftSidebar';
class App extends Component {
constructor() {
super() // gives component context of this instead of parent this
this.state = {
leftBarOpen : false
}
}
notifyOpen = () => {
console.log('opened') // works
this.setState({leftBarOpen: true});
/*** need to pass down to child component and $watch somehow... ***/
}
render() {
return (
<MuiThemeProvider muiTheme={getMuiTheme(darkBaseTheme)}>
<div className="App">
<Header onOpenLeftBar={this.notifyOpen} />
<Body />
<LeftSidebar listenForOpen={this.state.leftBarOpen} />
<Footer />
</div>
</MuiThemeProvider>
);
}
}
export default App;
// LeftSidebar
import React, { Component } from 'react';
import Drawer from 'material-ui/Drawer';
import MenuItem from 'material-ui/MenuItem';
import IconButton from 'material-ui/IconButton';
import NavigationClose from 'material-ui/svg-icons/navigation/close';
class LeftNavBar extends Component {
/** unsure if necessary here **/
constructor(props, state) {
super(props, state)
this.state = {
leftBarOpen : this.props.leftBarOpen
}
}
/** closing functionality works **/
close = () => {
this.setState({leftBarOpen: false});
}
render() {
return (
<Drawer open={this.state.leftBarOpen}>
<IconButton onClick={this.close}>
<NavigationClose />
</IconButton>
<MenuItem>Menu Item</MenuItem>
<MenuItem>Menu Item 2</MenuItem>
</Drawer>
);
}
}
export default LeftSidebar;
353
Free your mind of concepts like "watchers". In React there is only state and props. When a component's state changes via this.setState(..) it will update all of its children in render.
Your code is suffering from a typical anti-pattern of duplicating state. If both the header and the sibling components want to access or update the same piece of state, then they belong in a common ancestor (App, in your case) and no where else.
(some stuff removed / renamed for brevity)
class App extends Component {
// don't need `constructor` can just apply initial state here
state = { leftBarOpen: false }
// probably want 'toggle', but for demo purposes, have two methods
open = () => {
this.setState({ leftBarOpen: true })
}
close = () => {
this.setState({ leftBarOpen: false })
}
render() {
return (
<div className="App">
<Header onOpenLeftBar={this.open} />
<LeftSidebar
closeLeftBar={this.close}
leftBarOpen={this.state.leftBarOpen}
/>
</div>
)
}
}
Now Header and LeftSidebar do not need to be classes at all, and simply react to props, and call prop functions.
const LeftSideBar = props => (
<Drawer open={props.leftBarOpen}>
<IconButton onClick={props.closeLeftBar}>
<NavigationClose />
</IconButton>
</Drawer>
)
Now anytime the state in App changes, no matter who initiated the change, your LeftSideBar will react appropriately since it only knows the most recent props
155
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