I'm trying to add the Carousel image slider from MaterializeCSS to a simple React component but i'm not able to initialize it! It would be very helpful to know where i should do it in my code
import React, { Component } from 'react';
import { M } from 'materialize-css/dist/js/materialize.min.js';
export default class Slider extends Component {
componentDidMount() {
var elem = document.querySelector('.carousel');
var instance = M.Carousel.init(elem, { duration: 200 });
}
render() {
return (
<div className="container center-align">
<h1 className="header pink-text">Slider</h1>
<div className="carousel">
<a className="carousel-item" href="#one!">
<img src="https://www.w3schools.com/images/picture.jpg" />
</a>
<a className="carousel-item" href="#two!">
<img src="../../public/images/lana/1.jpg" />
</a>
<a className="carousel-item" href="#three!">
<img src="../../public/images/lana/1.jpg" />
</a>
<a className="carousel-item" href="#four!">
<img src="../../public/images/lana/1.jpg" />
</a>
<a className="carousel-item" href="#five!">
<img src="../../public/images/lana/1.jpg" />
</a>
</div>
</div>
);
}
}
this gives me an Error:
Cannot read property 'Carousel' of undefined
i tried to do it with Jquery, no errors but didn't work!
I had the same issue.
Solved it by adding the materializecss npm module
npm install materialize-css
and then importing it into the component
import M from "materialize-css";
and in the componentDidUpdate method, added the init
componentDidUpdate() {
let collapsible = document.querySelectorAll(".collapsible");
M.Collapsible.init(collapsible, {});
}
Problem solved!!
Using React Hook with useEffect you can also initialize each feature on Materialize, for example:
import React, { useEffect, Fragment } from "react";
import M from "materialize-css/dist/js/materialize.min.js";
useEffect(() => {
// Init Tabs Materialize JS
let tabs = document.querySelectorAll(".tabs");
M.Tabs.init(tabs);
});
In my case, I used tabs to initialize the Materialize feature.
Looks like you're using a .min file to import M from. You should install MaterializeCSS as a node module instead. You're getting an error because M is not defined as anything. There aren't any exports from that .min file.
If you want to wait until the script has loaded it is better to do that with a callback instead of setTimeout.
function loadScript(url, callback) {
var script = document.createElement("script")
script.type = "text/javascript";
if (callback) {
script.onload = callback;
}
document.body.appendChild(script)
script.src = url;
}
loadScript(pathtoscript, function() {
alert('script ready!');
});
If you want to use min.js file in your application, try adding it in html file using tag.
Alternatively try adding node modules using npm package.
Hope this helps.
I figured out that it needs some time to render the content. When I use setTimeout() function and call that initialization JS lines it worked.
I initialize the Carousel js code from the main html page with setTimeout() function, i used a spinner to make look little better
it looks like this
<script>
setTimeout(() => {
var elem = document.querySelector('.carousel');
var instance = M.Carousel.init(elem, {});
if (document.querySelector('.photos').classList) {
document.querySelector('.photos').classList.remove("spinner")
}
}, 2000)
</script>
add window.M. ...
useEffect(() => {
var elem = document.querySelector(".carousel");
var instance = window.M.Carousel.init(elem, {
fullWidth: true,
indicators: true,
});
});
I am using pay pals react engine. I have my layout component which calls my Nav component. Since Nav is global I wanted to put it within Layout, both seem to be rendered server side. The problem comes when I want to use react routers Link function in Nav.
Layout:
var React = require('react');
var Nav = require('../../server/components/Nav.jsx');
module.exports = React.createClass({
componentDidMount: function(){
try{Typekit.load({ async: true });}catch(e){}
},
render: function render() {
return (
<html>
<head>
<meta charSet='utf-8' />
<link rel="stylesheet" type="text/css" href="/css/main.css" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<title>
{this.props.title}
</title>
</head>
<body>
{ /*trying to pass router as a prop as a useless attempt to make this work*/ }
<Nav router={this.props.router} />
<div className="wrap">
{this.props.children}
</div>
</body>
<script src='/bundle.js'></script>
</html>
);
}
});
Here is my Nav component. You can see within the UL tag I am using anchor elements. I would like the use the tag so react router will do its thing rather than having to send a new request to the server. I've tried a few different things to make it would however I've been unsuccessful. Is it even possible to use react router in a component rendered from the server?
var React = require('react');
var Logo = require('./logo.jsx');
var Nav = React.createClass({
render: function(){
var mobileMenuShow = function(e){
var el = e.currentTarget;
var list = document.querySelector('.main-nav-list');
if(el.innerHTML === '+'){
el.innerHTML = '-';
list.setAttribute('class', 'main-nav-list open');
} else{
el.innerHTML = '+';
list.setAttribute('class', 'main-nav-list');
}
};
return (
<nav className="background-first main-nav">
<section className="nav-wrap">
<section className="main-nav-left">
<div className="main-nav-logo"><Logo /></div>
<div className="plus-icon" onClick={mobileMenuShow}>+</div>
</section>
<section className="main-nav-right">
<ul ref="navList" className="main-nav-list">
<li>Sign Up</li>
<li>Log In</li>
<li>Quick Start</li>
<li>Docs</li>
<li>About</li>
</ul>
</section>
</section>
</nav>
)
}
});
module.exports = Nav;
Is it possible, yes. As long as you have a client router kick off after the page is rendered from the server. Basically, if the only router in on the server, then it will always handle the requests. But, if you have one loaded in the client too, then it will pick up the client transitions and only use the server when you do a page reload (F5) or enter a new URL. Check out the React Router Mega Demo to see how the client.js file is also creating a router after the app is loaded from the server.
To accomplish the Link / <li> issue, you just need to create a component to return the link inside of a tab.
Here's an example of how to accomplish this (taken from issue 666).
var NavTab = React.createClass({
contextTypes: {
router: router: React.PropTypes.func
},
render: function () {
var isActive = this.context.router.isActive(this.props.to, this.props.params, this.props.query);
var className = isActive ? 'active' : '';
var link = (
<Link {...this.props} />
);
return <li className={className}>{link}</li>;
}
});
I have an app where I need to set the height of an element (lets say "app-content") dynamically. It takes the height of the "chrome" of the app and subtracts it and then sets the height of the "app-content" to fit 100% within those constraints. This is super simple with vanilla JS, jQuery, or Backbone views, but I'm struggling to figure out what the right process would be for doing this in React?
Below is an example component. I want to be able to set app-content's height to be 100% of the window minus the size of the ActionBar and BalanceBar, but how do I know when everything is rendered and where would I put the calculation stuff in this React Class?
/** #jsx React.DOM */
var List = require('../list');
var ActionBar = require('../action-bar');
var BalanceBar = require('../balance-bar');
var Sidebar = require('../sidebar');
var AppBase = React.createClass({
render: function () {
return (
<div className="wrapper">
<Sidebar />
<div className="inner-wrapper">
<ActionBar title="Title Here" />
<BalanceBar balance={balance} />
<div className="app-content">
<List items={items} />
</div>
</div>
</div>
);
}
});
module.exports = AppBase;
componentDidMount()
This method is called once after your component is rendered. So your code would look like so.
var AppBase = React.createClass({
componentDidMount: function() {
var $this = $(ReactDOM.findDOMNode(this));
// set el height and width etc.
},
render: function () {
return (
<div className="wrapper">
<Sidebar />
<div className="inner-wrapper">
<ActionBar title="Title Here" />
<BalanceBar balance={balance} />
<div className="app-content">
<List items={items} />
</div>
</div>
</div>
);
}
});
One drawback of using componentDidUpdate, or componentDidMount is that they are actually executed before the dom elements are done being drawn, but after they've been passed from React to the browser's DOM.
Say for example if you needed set node.scrollHeight to the rendered node.scrollTop, then React's DOM elements may not be enough. You need to wait until the elements are done being painted to get their height.
Solution:
Use requestAnimationFrame to ensure that your code is run after the painting of your newly rendered object
scrollElement: function() {
// Store a 'this' ref, and
var _this = this;
// wait for a paint before running scrollHeight dependent code.
window.requestAnimationFrame(function() {
var node = _this.getDOMNode();
if (node !== undefined) {
node.scrollTop = node.scrollHeight;
}
});
},
componentDidMount: function() {
this.scrollElement();
},
// and or
componentDidUpdate: function() {
this.scrollElement();
},
// and or
render: function() {
this.scrollElement()
return [...]
In my experience window.requestAnimationFrame wasn't enough to ensure that the DOM had been fully rendered / reflow-complete from componentDidMount. I have code running that accesses the DOM immediately after a componentDidMount call and using solely window.requestAnimationFrame would result in the element being present in the DOM; however, updates to the element's dimensions aren't reflected yet since a reflow hasn't yet occurred.
The only truly reliable way for this to work was to wrap my method in a setTimeout and a window.requestAnimationFrame to ensure React's current call stack gets cleared before registering for the next frame's render.
function onNextFrame(callback) {
setTimeout(function () {
requestAnimationFrame(callback)
})
}
If I had to speculate on why this is occurring / necessary I could see React batching DOM updates and not actually applying the changes to the DOM until after the current stack is complete.
Ultimately, if you're using DOM measurements in the code you're firing after the React callbacks you'll probably want to use this method.
Just to update a bit this question with the new Hook methods, you can simply use the useEffect hook:
import React, { useEffect } from 'react'
export default function App(props) {
useEffect(() => {
// your post layout code (or 'effect') here.
...
},
// array of variables that can trigger an update if they change. Pass an
// an empty array if you just want to run it once after component mounted.
[])
}
Also if you want to run before the layout paint use the useLayoutEffect hook:
import React, { useLayoutEffect } from 'react'
export default function App(props) {
useLayoutEffect(() => {
// your pre layout code (or 'effect') here.
...
}, [])
}
You can change the state and then do your calculations in the setState callback. According to the React documentation, this is "guaranteed to fire after the update has been applied".
This should be done in componentDidMount or somewhere else in the code (like on a resize event handler) rather than in the constructor.
This is a good alternative to window.requestAnimationFrame and it does not have the issues some users have mentioned here (needing to combine it with setTimeout or call it multiple times). For example:
class AppBase extends React.Component {
state = {
showInProcess: false,
size: null
};
componentDidMount() {
this.setState({ showInProcess: true }, () => {
this.setState({
showInProcess: false,
size: this.calculateSize()
});
});
}
render() {
const appStyle = this.state.showInProcess ? { visibility: 'hidden' } : null;
return (
<div className="wrapper">
...
<div className="app-content" style={appStyle}>
<List items={items} />
</div>
...
</div>
);
}
}
I feel that this solution is dirty, but here we go:
componentDidMount() {
this.componentDidUpdate()
}
componentDidUpdate() {
// A whole lotta functions here, fired after every render.
}
Now I am just going to sit here and wait for the down votes.
React has few lifecycle methods which help in these situations, the lists including but not limited to getInitialState, getDefaultProps, componentWillMount, componentDidMount etc.
In your case and the cases which needs to interact with the DOM elements, you need to wait till the dom is ready, so use componentDidMount as below:
/** #jsx React.DOM */
var List = require('../list');
var ActionBar = require('../action-bar');
var BalanceBar = require('../balance-bar');
var Sidebar = require('../sidebar');
var AppBase = React.createClass({
componentDidMount: function() {
ReactDOM.findDOMNode(this).height = /* whatever HEIGHT */;
},
render: function () {
return (
<div className="wrapper">
<Sidebar />
<div className="inner-wrapper">
<ActionBar title="Title Here" />
<BalanceBar balance={balance} />
<div className="app-content">
<List items={items} />
</div>
</div>
</div>
);
}
});
module.exports = AppBase;
Also for more information about lifecycle in react you can have look the below link:
https://facebook.github.io/react/docs/state-and-lifecycle.html
I ran into the same problem.
In most scenarios using the hack-ish setTimeout(() => { }, 0) in componentDidMount() worked.
But not in a special case; and I didn't want to use the ReachDOM findDOMNode since the documentation says:
Note: findDOMNode is an escape hatch used to access the underlying DOM
node. In most cases, use of this escape hatch is discouraged because
it pierces the component abstraction.
(Source: findDOMNode)
So in that particular component I had to use the componentDidUpdate() event, so my code ended up being like this:
componentDidMount() {
// feel this a little hacky? check this: http://stackoverflow.com/questions/26556436/react-after-render-code
setTimeout(() => {
window.addEventListener("resize", this.updateDimensions.bind(this));
this.updateDimensions();
}, 0);
}
And then:
componentDidUpdate() {
this.updateDimensions();
}
Finally, in my case, I had to remove the listener created in componentDidMount:
componentWillUnmount() {
window.removeEventListener("resize", this.updateDimensions.bind(this));
}
There is actually a lot simpler and cleaner version than using request animationframe or timeouts. Iam suprised no one brought it up:
the vanilla-js onload handler.
If you can, use component did mount, if not, simply bind a function on the onload hanlder of the jsx component. If you want the function to run every render, also execute it before returning you results in the render function. the code would look like this:
runAfterRender = () =>
{
const myElem = document.getElementById("myElem")
if(myElem)
{
//do important stuff
}
}
render()
{
this.runAfterRender()
return (
<div
onLoad = {this.runAfterRender}
>
//more stuff
</div>
)
}
}
I'm actually having a trouble with similar behaviour, I render a video element in a Component with it's id attribute so when RenderDOM.render() ends it loads a plugin that needs the id to find the placeholder and it fails to find it.
The setTimeout with 0ms inside the componentDidMount() fixed it :)
componentDidMount() {
if (this.props.onDidMount instanceof Function) {
setTimeout(() => {
this.props.onDidMount();
}, 0);
}
}
After render, you can specify the height like below and can specify the height to corresponding react components.
render: function () {
var style1 = {height: '100px'};
var style2 = { height: '100px'};
//window. height actually will get the height of the window.
var hght = $(window).height();
var style3 = {hght - (style1 + style2)} ;
return (
<div className="wrapper">
<Sidebar />
<div className="inner-wrapper">
<ActionBar style={style1} title="Title Here" />
<BalanceBar style={style2} balance={balance} />
<div className="app-content" style={style3}>
<List items={items} />
</div>
</div>
</div>
);`
}
or you can specify the height of the each react component using sass. Specify first 2 react component main div's with fixed width and then the third component main div's height with auto. So based on the third div's content the height will be assigned.
For me, no combination of window.requestAnimationFrame or setTimeout produced consistent results. Sometimes it worked, but not always—or sometimes it would be too late.
I fixed it by looping window.requestAnimationFrame as many times as necessary.
(Typically 0 or 2-3 times)
The key is diff > 0: here we can ensure exactly when the page updates.
// Ensure new image was loaded before scrolling
if (oldH > 0 && images.length > prevState.images.length) {
(function scroll() {
const newH = ref.scrollHeight;
const diff = newH - oldH;
if (diff > 0) {
const newPos = top + diff;
window.scrollTo(0, newPos);
} else {
window.requestAnimationFrame(scroll);
}
}());
}
For me, componentDidUpdate alone or window.requestAnimationFrame alone didn't solve the problem, but the following code worked.
// Worked but not succinct
componentDidUpdate(prevProps, prevState, snapshot) {
if (this.state.refreshFlag) { // in the setState for which you want to do post-rendering stuffs, set this refreshFlag to true at the same time, to enable this block of code.
window.requestAnimationFrame(() => {
this.setState({
refreshFlag: false // Set the refreshFlag back to false so this only runs once.
});
something = this.scatterChart.current.canvas
.toDataURL("image/png"); // Do something that need to be done after rendering is finished. In my case I retrieved the canvas image.
});
}
}
And later I tested with requestAnimationFrame commented, it still worked perfectly:
// The best solution I found
componentDidUpdate(prevProps, prevState, snapshot) {
if (this.state.refreshFlag) { // in the setState for which you want to do post-rendering stuffs, set this refreshFlag to true at the same time, to enable this block of code.
// window.requestAnimationFrame(() => {
this.setState({
refreshFlag: false // Set the refreshFlag back to false so this only runs once.
});
something = this.scatterChart.current.canvas
.toDataURL("image/png"); // Do something that need to be done after rendering is finished. In my case I retrieved the canvas image.
// });
}
}
I'm not sure whether it's just a coincidence that the extra setState induced a time delay, so that when retrieving the image, the drawing is already done (I will get the old canvas image if I remove the setState).
Or more possibly, it was because setState is required to be executed after everything is rendered, so it forced the waiting for the rendering to finish.
-- I tend to believe the latter, because in my experience, calling setState consecutively in my code will result in each one triggered only after the last rendering finished.
Lastly, I tested the following code. If this.setState({}); doesn't update the component, but wait till the rendering finishes, this would be the ultimate best solution, I thought. However, it failed. Even when passing an empty {}, setState() still updates the component.
// This one failed!
componentDidUpdate(prevProps, prevState, snapshot) {
// if (this.state.refreshFlag) {
// window.requestAnimationFrame(() => {
this.setState({});
something = this.scatterChart.current.canvas
.toDataURL("image/png");
// });
// }
}
I recommend that you make use of hooks.
They are available from version 16.8.0 onwards.
You can check the behavior of this hook in the official react documentation.
Something like this:
import React, { useEffect } from 'react'
const AppBase = ({ }) => {
useEffect(() => {
// set el height and width etc.
}, [])
return (
<div className="wrapper">
<Sidebar />
<div className="inner-wrapper">
<ActionBar title="Title Here" />
<BalanceBar balance={balance} />
<div className="app-content">
<List items={items} />
</div>
</div>
</div>
);
}
export default AppBase
I had weird situation when i need to print react component which receives big amount of data and paint in on canvas. I've tried all mentioned approaches, non of them worked reliably for me, with requestAnimationFrame inside setTimeout i get empty canvas in 20% of the time, so i did the following:
nRequest = n => range(0,n).reduce(
(acc,val) => () => requestAnimationFrame(acc), () => requestAnimationFrame(this.save)
);
Basically i made a chain of requestAnimationFrame's, not sure is this good idea or not but this works in 100% of the cases for me so far (i'm using 30 as a value for n variable).
I am not going to pretend I know why this particular function works, however window.getComputedStyle works 100% of the time for me whenever I need to access DOM elements with a Ref in a useEffect — I can only presume it will work with componentDidMount as well.
I put it at the top of the code in a useEffect and it appears as if it forces the effect to wait for the elements to be painted before it continues with the next line of code, but without any noticeable delay such as using a setTimeout or an async sleep function. Without this, the Ref element returns as undefined when I try to access it.
const ref = useRef(null);
useEffect(()=>{
window.getComputedStyle(ref.current);
// Next lines of code to get element and do something after getComputedStyle().
});
return(<div ref={ref}></div>);
for functional components you can react-use-call-onnext-render, its a custom hook that allows schedule callback on a later render.
It is used successfully on one of my other projects.
for requiring dimension of a dom element,
see this example,its the third example on react-use-call-onnext-render examples:
let's say we want to get dimensions of a removable DOM element,lets say div that is controlled by showBox state
variable. for that we can use getBoundingClientRect(). however, we want to call this function only after the element
mounted into the dom, so will schedule this call one render after the variable responsible for showing this element
in the dom has changed,and this variable is showBox, so he will be dependency of useCallOnNextRender:
const YourComponent = () => {
const [showBox, setShowBox] = useState(false)
const divRef = useRef()
const callOnNextShowBoxChange = useCallOnNextRender()
return (
<>
<div style={canvasStyle} id="canvas">
<button style={boxStyle} onClick={() => {
setShowBox(!showBox)
callOnNextShowBoxChange(() => console.log(divRef.current.getBoundingClientRect())) //right value
}}>toggle show box
</button>
<div style={{border: "black solid 1px"}} ref={divRef}>
{showBox ? <div style={boxStyle}>box2</div> : null}
</div>
</div>
</>
);
};
After trying all the suggested solutions above with no luck I found one of my elements in the middle had CSS transition, that's why I failed to get correct computed geometry after props changed.
So I had to use onTransitionEnd listener to wait for a moment when to try getting the computed by DOM height of container element.
Hope this will save someone's work day lol.
From the ReactDOM.render() documentation:
If the optional callback is provided, it will be executed after the
component is rendered or updated.
A little bit of update with ES6 classes instead of React.createClass
import React, { Component } from 'react';
class SomeComponent extends Component {
constructor(props) {
super(props);
// this code might be called when there is no element avaliable in `document` yet (eg. initial render)
}
componentDidMount() {
// this code will be always called when component is mounted in browser DOM ('after render')
}
render() {
return (
<div className="component">
Some Content
</div>
);
}
}
Also - check React component lifecycle methods:The Component Lifecycle
Every component have a lot of methods similar to componentDidMount eg.
componentWillUnmount() - component is about to be removed from browser DOM