I'm using mxGraph in a React Single Page Application and instantiating a new mxKeyHandler in componentDidMount. I also invoke its destroy method in componentWillUnmount. It all works fine the first time you visit the page that has the mxGraph component, but if I navigate away to a different page and come back (without a page refresh), it no longer works.
componentDidMount() {
this.editor = new mxEditor();
this.editor.setGraphContainer(this.mxGraphRef.current);
......
this.keyHandler = new mxKeyHandler(this.editor.graph);
this.keyHandler.bindKey(46, evt => {
this.editor.graph.removeCells();
});
}
componentWillUnmount() {
this.keyHandler.destroy();
this.editor.destroy();
}
Any advice as to what I'm doing wrong?
Ok, the solution was to add the following 2 lines:
this.editor.graph.container.setAttribute('tabindex', '-1');
this.editor.graph.container.focus();
As described here: https://jgraph.github.io/mxgraph/docs/known-issues.html#Focus
Related
React Native Navigation Refresh List Screen on back:
this.props.navigation.navigate('Order List', {
order_id: this.state.order_id,
order_status: this.state.od_status,
})
What you want to achive isn't clear, but if want to modify your list of data when going back to your previous screen you could simply use useEffect and modify your list in there.
Note: Your list has to be stored in a local state otherwise the screen wouldn't re-render when updating the list and youl would see no changes on your screen.
better description of the problem would be helpful, but this is general solution for class based components:
componentDidMount() {
this._unsubscribe = this.props.navigation.addListener('focus', () => {
this.loadDataFunction();
}
}
componentWillUnmount() {
this._unsubscribe();
}
I am using Facebook's like button as generated by facebook's like button configurator. However in order to get facebook-sdk to finish loading before the Like button, I had to use something called react-load-script and make a my own wrapper component for the like button html I got from the configurator.
my like button
class Like extends React.Component {
state = {
facebookLoaded: false
};
handleFacebookLoaded = () => this.setState({
facebookLoaded: true
});
FacebookSDK = () => <>
<div id="fb-root"></div>
<Script
async defer crossOrigin="anonymous"
url="https://connect.facebook.net/en_US/sdk.js#xfbml=1&version=v3.3&appId=391623981325884&autoLogAppEvents=1"
onLoad={this.handleFacebookLoaded}
/>
</>;
render() {
return <>
<this.FacebookSDK />
{this.state.facebookLoaded
? <div class="fb-like" data-href={this.props.url} data-width="" data-layout="button_count" data-action="like" data-size="large" data-show-faces="true" data-share="true" />
: null}
</>;
}
}
In my code all the script loading stuff actually happens in App.jsx, but I moved it into one class just to show a simple version.
This part seems to work fine, the issue lies when changing the url passed to data-href.
I checked the react dom in the browser and the data-href is actually being updated properly, however this does not affect the actual url that is being used by the like button, unless I do a full page refresh. I'm assuming this has to do with how the data-href is being used by facebook-sdk. (edit: after testing I'm not sure anymore)
I've found many questions about this on Stack Overflow, however none of them seem to be based off the CDN version of facebook buttons
From what I understand, the div containing the href needs to be placed out and back into the DOM in order for the facebook-sdk to detect a change, but I don't know how to do this in react without a full page refresh. Also I'm not certain this is even the right solution.
-- Update --
I just noticed something else that seems like useful information. If I navigate to the page with the like button, then it doesn't show up. It will only show up if the page refreshes. I tested it by moving the part that loads the script into the like component (like in the example shown above) and that didn't change the behavior at all.
-- more experimenting --
I wrote an event handler that takes all the facebook related jsx out of the dom and back in (by toggling a button) However when all the code goes back into the dom (both jsx and html), the UI for the button does not come back. I'm really now sure how this is possible as I'm literally reloading the script and everything facebook related so this should be equivalent to a page refresh no?
I fixed the issue thanks to misorude. The part I was missing was calling window.FB.XFBML.parse(). I didn't realize I could access FB the same way using the CDN. If anyone is looking for a react solution here is the working code:
class Like extends React.Component {
constructor(props) {
super(props);
this.state = {
url: props.url,
}
}
handleChangePage() {
let likeBtn = document.createElement('div');
likeBtn.className = "fb-like";
likeBtn.setAttribute("data-href", this.props.url);
likeBtn.setAttribute("data-width", "");
likeBtn.setAttribute("data-layout", "button_count");
likeBtn.setAttribute("data-action", "like");
likeBtn.setAttribute("data-size", "large");
likeBtn.setAttribute("data-show-faces", "true");
likeBtn.setAttribute("data-share", "true");
let likePanel = document.getElementById("like-panel");
likePanel.removeChild(likePanel.childNodes[0]);
likePanel.appendChild(likeBtn);
window.FB.XFBML.parse(likePanel)
this.setState({ url: this.props.url });
}
componentDidMount() {
this.handleChangePage();
}
render() {
if(this.props.url !== this.state.url)
this.handleChangePage();
return <div id="like-panel">
{this.props.facebookLoaded
? <div className="fb-like" data-href={this.props.url} data-width="" data-layout="button_count" data-action="like" data-size="large" data-show-faces="true" data-share="true" />
: null}
</div>;
}
}
I moved the CDN out of this component so that it only loads the sdk once for the whole app.
It must be pretty regular issue.
I'm passing props down to the children and I'm using it there to request to the endpoint. More detailed: I'm clicking on the list item, I'm checking which item was clicked, I'm passing it to the child component and there basing on prop I passed I'd like to request certain data. All works fine and I'm getting what I need, but only for the first time, ie. when refreshing page incoming props are gone and I cannot construct proper URL where as a query I'd like to use the prop value. Is there a way to preserve the prop so when the page will be refresh it will preserve last prop.
Thank you!
(You might want to take a look at: https://github.com/rt2zz/redux-persist, it is one of my favorites)
Just like a normal web application if the user reloads the page you're going to have your code reloaded. The solution is you need to store the critical data somewhere other than the React state if you want it to survive.
Here's a "template" in pseudo code. I just used a "LocalStorage" class that doesn't exist. You could pick whatever method you wanted.
class Persist extends React.Component {
constuctor(props) {
this.state = {
criticalData = null
}
}
componentDidMount() {
//pseudo code
let criticalData = LocalStorage.get('criticalData')
this.setState({
criticalData: criticalData
})
}
_handleCriticalUpdate(update) {
const merge = {
...LocalStorage.get('criticalData')
...update
}
LocalStorage.put('criticalData', merge)
this.setState({
criticalData: merge
})
}
render() {
<div>
...
<button
onClick={e => {
let update = ...my business logic
this._handleCriticalUpdate(update) //instead of set state
}}
>
....
</div>
}
}
By offloading your critical data to a cookie or the local storage you are injecting persistence into the lifecycle of the component. This means when a user refreshes the page you keep your state.
I hope that helps!
I need to check between Facebook's expiration date and the current date when I enter in two different components. Dashboard and Pages. Both have this:
componentWillMount() {
const { linkedAccount, clearLinkedAccounts, getFacebookPages } = this.props
const now = moment().format('YYYY-MM-DD HH:mm:ss')
if (linkedAccount) {
if (now < linkedAccount.expiresIn) {
getFacebookPages()
} else {
clearLinkedAccounts()
}
}
}
componentWillUnmount() {
const { linkedAccount, clearLinkedAccounts } = this.props
const now = moment().format('YYYY-MM-DD HH:mm:ss')
if (linkedAccount && now > linkedAccount.expiresIn) {
clearLinkedAccounts()
}
}
But only when refreshing the page manually, the clearLinkedAccounts() is executed, by running componentWillMount, but before leaving it, it doesn't. I want it to be executed, if necessary, before entering in another route.
Refreshing the page is not like going from a page to another page inside the same single app context. React router allows you to go from a page to another within a React single app with tag like Link. It is why react router is so useful!
When you click on a link to go to another page with Link, the React single app is still active. As a result, componentWillUnmount wil lbe called because the single app is able to unmount component.
When you refresh the page (F5), a new page is loaded. As a result, the entire existing single app is removed and given to the browser garbage collector. In that case, you have no control on React component. So impossible to call componentWillUnmount because there is no more components at all.
Background
I am building an app with the following details
react
react-router
redux
it is universal javascript
node js
Problem
When routing with the Link tag from component to component it works perfectly. It calls the data that the component requires and renders the page. But when I click on a Link that uses the same component as the current one all I see is the url change.
Attempts
Things I have tried to get this to work.
Attempt 1
So far I have tried the steps in this question but the solution wont work for me. This was the code I implemented
componentWillReceiveProps(nextProps) {
if (nextProps.article.get('id') !== this.props.article.get('id')) {
console.log('i got trigggerd YESSSSSSSSSSSSSSS');
}
}
But the variable nextProps is always the same as the current props.
Attempt 2
I decided to call the same code I use in componentWillMount but that didn't work either.
componentWillMount() {
let { category, slug } = this.props.params;
this.props.loadArticleState({ category, slug });
}
It just creates an infinite loop when I put this into componentWillReceiveProps.
Conclusion
I belief the problem is clicking the link never calls the data associated with it. Since the data is loaded with
static fetchData({ store, params }) {
let { category, slug } = params;
return store.dispatch(loadArticleState({ category, slug }));
}
Any help is appreciated.
Solution I Used
I created a function to test if the previous data is the same as the changed data.
compareParams(prevProps, props) {
if (!prevProps || typeof prevProps.params !== typeof props.params) {
return false;
}
return Object.is(props.params, prevProps.params);
}
So this tests
are there any previous props?
and then if the props are equal to the previous props?
then return false if there are if this is the case
if not then we see compare props and previous props parameters
In ComponentDidUpdate
In the compoonentDidUpdate we use this function to determine if the data should be updated
componentDidUpdate(prevProps) {
if (this.compareParams(prevProps, this.props)) {
return;
}
this.props[this.constructor.reducerName](this.props.params);
}
Conclusion
This code updates the body of a page that uses the same react component if it receives new data.
maybe you can try use onChange event on Route component, check Route API and then signal to child component that refresh is needed...