Develop Reference

React error 185- I know the issue but how can I call setState once

Here's the relevant code-
CONFIG.theme.activeScheme ? react.createElement(SortBox, {
onChange: this.updateColourScheme.bind(this),
onnewschemes: this.setState({}),
// TODO: Make this compatible with the changes to the theme install process: need to create a method to update the scheme options without a full reload.
sortBoxOptions: generateSchemesOptions(CONFIG.theme.schemes),
// It doesn't work when I directly use CONFIG.theme.activeScheme in the sortBySelectedFn
// because it hardcodes the value into the fn
sortBySelectedFn: (a) => a.key === this.getActiveScheme(),
}) : null,
My preferred end result is to be able to reload JUST the sortbox component using an via the onnewschemes event(I pretty much need to refresh all of the options within a little drop down method from outside the render itself.)
The event dispatcher i have looks like so:
const schemeSelector = document.querySelector("div.marketplace-header > div > div");
const newSchemeEvent = new CustomEvent("newschemes", {
bubbles: true,
detail: { schemes: () => parsedSchemes },
});
schemeSelector.dispatchEvent(newSchemeEvent);

Pass value from map to state

//It's working now - updated code
I'm working on my own autocomplete component because I have problem with passing firebase data to a ready one.
The whole mechanism is working good but I have problem with passing values after getting user input
I'm setting initial state with those values
const INITIAL_STATE = {
allChars: [],
suggestions: [],
value: ""
};
Then in autocomplete class i'm loading all users from database
loadData(){
let self = this;
let characters = firebase.firestore().collection("users");
characters.get().then((querySnapshot) => {
querySnapshot.forEach((doc) => {
let document = doc.data();
self.setState(({allChars})=>({
allChars: [
...allChars,
document
]
}))
});
});
}
Here is my getSuggestions function. It is firing on input change
getSuggestions = event => {
const {value, suggestions} = event.target;
this.setState({
value: value,
suggestions: []
})
let suggest = [];
this.state.allChars.map((allChars) => {
if(value.length > 1 && allChars.name.toLowerCase().includes(value.toLowerCase())){
suggest.push (
allChars.name
);
}
})
this.setState({
suggestions: suggest
})
}
In render I just put {sugestions}
But in {suggestions} I get rendered only one name.
one
But when I console.log it - I get two names
two
There should be two.
I tried to set state in this function like in loadData(), but I still get only one value.
Is there other way to get both values into DOM
Full code can be found here: https://github.com/Ilierette/react-planner/blob/master/src/component/elements/Autocomplete.js

I think the reason you are just seeing one element each time your components re-render is that in your map function on your allChars array, when you want to update the suggestions in your state, you are setting just the name each time as a new array while you should update the existing array in your state, so your code should be:
this.setState({
suggestions: [...this.state.suggestions, allChars.name]
})

Merge events from a changing list of Observables

I'm using rxjs.
I have a Browser that's responsible for a number of Page objects. Each page has an Observable<Event> that yields a stream of events.
Page objects are closed and opened at various times. I want to create one observable, called TheOneObservable that will merge all the events from all the currently active Page objects, and also merge in custom events from the Browser object itself.
Closing a Page means that the subscription to it should be closed so it doesn't prevent it from being GC'd.
My problem is that Pages can be closed at any time, which means that the number of Observables being merged is always changing. I've thought of using an Observable of Pages and using mergeMap, but there are problems with this. For example, a subscriber will only receive events of Pages that are opened after it subscribes.
Note that this question has been answered here for .NET, but using an ObservableCollection that isn't available in rxjs.
Here is some code to illustrate the problem:
class Page {
private _events = new Subject<Event>();
get events(): Observable<Event> {
return this._events.asObservable();
}
}
class Browser {
pages = [] as Page[];
private _ownEvents = new Subject<Event>();
addPage(page : Page) {
this.pages.push(page);
}
removePage(page : Page) {
let ixPage = this.pages.indexOf(page);
if (ixPage < 0) return;
this.pages.splice(ixPage, 1);
}
get oneObservable() {
//this won't work for aforementioned reasons
return Observable.from(this.pages).mergeMap(x => x.events).merge(this._ownEvents);
}
}
It's in TypeScript, but it should be understandable.

You can switchMap() on a Subject() linked to array changes, replacing oneObservable with a fresh one when the array changes.
pagesChanged = new Rx.Subject();
addPage(page : Page) {
this.pages.push(page);
this.pagesChanged.next();
}
removePage(page : Page) {
let ixPage = this.pages.indexOf(page);
if (ixPage < 0) return;
this.pages.splice(ixPage, 1);
this.pagesChanged.next();
}
get oneObservable() {
return pagesChanged
.switchMap(changeEvent =>
Observable.from(this.pages).mergeMap(x => x.events).merge(this._ownEvents)
)
}
Testing,
const page1 = { events: Rx.Observable.of('page1Event') }
const page2 = { events: Rx.Observable.of('page2Event') }
let pages = [];
const pagesChanged = new Rx.Subject();
const addPage = (page) => {
pages.push(page);
pagesChanged.next();
}
const removePage = (page) => {
let ixPage = pages.indexOf(page);
if (ixPage < 0) return;
pages.splice(ixPage, 1);
pagesChanged.next();
}
const _ownEvents = Rx.Observable.of('ownEvent')
const oneObservable =
pagesChanged
.switchMap(pp =>
Rx.Observable.from(pages)
.mergeMap(x => x.events)
.merge(_ownEvents)
)
oneObservable.subscribe(x => console.log('subscribe', x))
console.log('adding 1')
addPage(page1)
console.log('adding 2')
addPage(page2)
console.log('removing 1')
removePage(page1)
.as-console-wrapper { max-height: 100% !important; top: 0; }
<script src="https://cdnjs.cloudflare.com/ajax/libs/rxjs/5.5.6/Rx.js"></script>

You will need to manage the subscriptions to the pages yourself and feed its events into the resulting subject yourself:
const theOneObservable$ = new Subject<Event>();
function openPage(page: Page): Subscription {
return page.events$.subscribe(val => this.theOneObservable$.next(val));
}
Closing the page, i.e. calling unsubscribe on the returned subscription, will already do everything it has to do.
Note that theOneObservable$ is a hot observable here.
You can, of course, take this a bit further by writing your own observable type which encapsulates all of this API. In particular, this would allow you to unsubscribe all inner observables when it is being closed.
A slightly different approach is this:
const observables$ = new Subject<Observable<Event>>();
const theOneObservable$ = observables$.mergeMap(obs$ => obs$);
// Add a page's events; note that takeUntil takes care of the
// unsubscription process here.
observables$.next(page.events$.takeUntil(page.closed$));
This approach is superior in the sense that it will unsubscribe the inner observables automatically when the observable is unsubscribed.

RxJS and React multiple clicked elements to form single data array

So I just started trying to learn rxjs and decided that I would implement it on a UI that I'm currently working on with React (I have time to do so, so I went for it). However, I'm still having a hard time wrapping my head around how it actually works... Not only "basic" stuff like when to actually use a Subject and when to use an Observable, or when to just use React's local state instead, but also how to chain methods and so on. That's all too broad though, so here's the specific problem I have.
Say I have a UI where there's a list of filters (buttons) that are all clickeable. Any time I click on one of them I want to, first of all, make sure that the actions that follow will debounce (as to avoid making network requests too soon and too often), then I want to make sure that if it's clicked (active), it will get pushed into an array and if it gets clicked again, it will leave the array. Now, this array should ultimately include all of the buttons (filters) that are currently clicked or selected.
Then, when the debounce time is done, I want to be able to use that array and send it via Ajax to my server and do some stuff with it.
import React, { Component } from 'react';
import * as Rx from 'rx';
export default class CategoryFilter extends Component {
constructor(props) {
super(props);
this.state = {
arr: []
}
this.click = new Rx.Subject();
this.click
.debounce(1000)
// .do(x => this.setState({
// arr: this.state.arr.push(x)
// }))
.subscribe(
click => this.search(click),
e => console.log(`error ---> ${e}`),
() => console.log('completed')
);
}
search(id) {
console.log('search --> ', id);
// this.props.onSearch({ search });
}
clickHandler(e) {
this.click.onNext(e.target.dataset.id);
}
render() {
return (
<section>
<ul>
{this.props.categoriesChildren.map(category => {
return (
<li
key={category._id}
data-id={category._id}
onClick={this.clickHandler.bind(this)}
>
{category.nombre}
</li>
);
})}
</ul>
</section>
);
}
}
I could easily go about this without RxJS and just check the array myself and use a small debounce and what not, but I chose to go this way because I actually want to try to understand it and then be able to use it on bigger scenarios. However, I must admit I'm way lost about the best approach. There are so many methods and different things involved with this (both the pattern and the library) and I'm just kind of stuck here.
Anyways, any and all help (as well as general comments about how to improve this code) are welcome. Thanks in advance!
---------------------------------UPDATE---------------------------------
I have implemented a part of Mark's suggestion into my code, but this still presents two problems:
1- I'm still not sure as to how to filter the results so that the array will only hold IDs for the buttons that are clicked (and active). So, in other words, these would be the actions:
Click a button once -> have its ID go into array
Click same button again (it could be immediately after the first
click or at any other time) -> remove its ID from array.
This has to work in order to actually send the array with the correct filters via ajax. Now, I'm not even sure that this is a possible operation with RxJS, but one can dream... (Also, I'm willing to bet that it is).
2- Perhaps this is an even bigger issue: how can I actually maintain this array while I'm on this view. I'm guessing I could use React's local state for this, just don't know how to do it with RxJS. Because as it currently is, the buffer returns only the button/s that has/have been clicked before the debounce time is over, which means that it "creates" a new array each time. This is clearly not the right behavior. It should always point to an existing array and filter and work with it.
Here's the current code:
import React, { Component } from 'react';
import * as Rx from 'rx';
export default class CategoryFilter extends Component {
constructor(props) {
super(props);
this.state = {
arr: []
}
this.click = new Rx.Subject();
this.click
.buffer(this.click.debounce(2000))
.subscribe(
click => console.log('click', click),
e => console.log(`error ---> ${e}`),
() => console.log('completed')
);
}
search(id) {
console.log('search --> ', id);
// this.props.onSearch({ search });
}
clickHandler(e) {
this.click.onNext(e.target.dataset.id);
}
render() {
return (
<section>
<ul>
{this.props.categoriesChildren.map(category => {
return (
<li
key={category._id}
data-id={category._id}
onClick={this.clickHandler.bind(this)}
>
{category.nombre}
</li>
);
})}
</ul>
</section>
);
}
}
Thanks, all, again!

Make your filter items an Observable streams of click events using Rx.Observable.fromevent (see https://github.com/Reactive-Extensions/RxJS/blob/master/doc/gettingstarted/events.md#converting-a-dom-event-to-a-rxjs-observable-sequence) - it understands a multi-element selector for the click handling.
You want to keep receiving click events until a debounce has been hit (user has enabled/disabled all filters she wants to use). You can use the Buffer operator for this with a closingSelector which needs to emit a value when to close the buffer and emit the buffered values.
But leaves the issue how to know the current actual state.
UPDATE
It seems to be far easier to use the .scan operator to create your filterState array and debounce these.
const sources = document.querySelectorAll('input[type=checkbox]');
const clicksStream = Rx.Observable.fromEvent(sources, 'click')
.map(evt => ({
name: evt.target.name,
enabled: evt.target.checked
}));
const filterStatesStream = clicksStream.scan((acc, curr) => {
acc[curr.name] = curr.enabled;
return acc
}, {})
.debounce(5 * 1000)
filterStatesStream.subscribe(currentFilterState => console.log('time to do something with the current filter state: ', currentFilterState);
(https://jsfiddle.net/crunchie84/n1x06016/6/)

Actually, your problem is about RxJS, not React itself. So it is easy. Suppose you have two function:
const removeTag = tagName =>
tags => {
const index = tags.indexOf(index)
if (index !== -1)
return tags
else
return tags.splice(index, 1, 0)
}
const addTag = tagName =>
tags => {
const index = tags.indexOf(index)
if (index !== -1)
return tags.push(tagName)
else
return tags
}
Then you can either using scan:
const modifyTags$ = new Subject()
modifyTags$.pipe(
scan((tags, action) => action(tags), [])
).subscribe(tags => sendRequest(tags))
modifyTags$.next(addTag('a'))
modifyTags$.next(addTag('b'))
modifyTags$.next(removeTag('a'))
Or having a separate object for tags:
const tags$ = new BehaviorSubject([])
const modifyTags$ = new Subject()
tags$.pipe(
switchMap(
tags => modifyTags$.pipe(
map(action => action(tags))
)
)
).subscribe(tags$)
tags$.subscribe(tags => sendRequest(tags))

How to fast render >10000 items using React + Flux?

I would like to ask what is the correct way to fast render > 10000 items in React.
Suppose I want to make a checkboxList which contain over dynamic 10000 checkbox items.
I make a store which contain all the items and it will be used as state of checkbox list.
When I click on any checkbox item, it will update the corresponding item by action and so the store is changed.
Since store is changed so it trigger the checkbox list update.
The checkbox list update its state and render again.
The problem here is if I click on any checkbox item, I have to wait > 3 seconds to see the checkbox is ticked. I don't expect this as only 1 checkbox item need to be re-rendered.
I try to find the root cause. The most time-consuming part is inside the checkbox list render method, related to .map which create the Checkbox component to form componentList.. But actually only 1 checkbox have to re-render.
The following is my codes.
I use ReFlux for the flux architecture.
CheckboxListStore
The Store store all the checkbox item as map. (name as key, state (true/false) as value)
const Reflux = require('reflux');
const Immutable = require('immutable');
const checkboxListAction = require('./CheckboxListAction');
let storage = Immutable.OrderedMap();
const CheckboxListStore = Reflux.createStore({
listenables: checkboxListAction,
onCreate: function (name) {
if (!storage.has(name)) {
storage = storage.set(name, false);
this.trigger(storage);
}
},
onCheck: function (name) {
if (storage.has(name)) {
storage = storage.set(name, true);
this.trigger(storage);
}
},
onUncheck: function (name) {
if (storage.has(name)) {
storage = storage.set(name, false);
this.trigger(storage);
}
},
getStorage: function () {
return storage;
}
});
module.exports = CheckboxListStore;
CheckboxListAction
The action, create, check and uncheck any checkbox item with name provided.
const Reflux = require('reflux');
const CheckboxListAction = Reflux.createActions([
'create',
'check',
'uncheck'
]);
module.exports = CheckboxListAction;
CheckboxList
const React = require('react');
const Reflux = require('reflux');
const $ = require('jquery');
const CheckboxItem = require('./CheckboxItem');
const checkboxListAction = require('./CheckboxListAction');
const checkboxListStore = require('./CheckboxListStore');
const CheckboxList = React.createClass({
mixins: [Reflux.listenTo(checkboxListStore, 'onStoreChange')],
getInitialState: function () {
return {
storage: checkboxListStore.getStorage()
};
},
render: function () {
const {storage} = this.state;
const LiComponents = storage.map((state, name) => {
return (
<li key = {name}>
<CheckboxItem name = {name} />
</li>
);
}).toArray();
return (
<div className = 'checkbox-list'>
<div>
CheckBox List
</div>
<ul>
{LiComponents}
</ul>
</div>
);
},
onStoreChange: function (storage) {
this.setState({storage: storage});
}
});
module.exports = CheckboxList;
CheckboxItem
Inside onChange callback, I call the action to update the item.
const React = require('react');
const Reflux = require('reflux');
const $ = require('jquery');
const checkboxListAction = require('./CheckboxListAction');
const checkboxListStore = require('./CheckboxListStore');
const CheckboxItem = React.createClass({
mixins: [Reflux.listenTo(checkboxListStore, 'onStoreChange')],
propTypes: {
name: React.PropTypes.string.isRequired
},
getInitialState: function () {
const {name} = this.props;
return {
checked: checkboxListStore.getStorage().get(name)
};
},
onStoreChange: function (storage) {
const {name} = this.props;
this.setState({
checked: storage.get(name)
});
},
render: function () {
const {name} = this.props;
const {checked} = this.state;
return (
<div className = 'checkbox' style = {{background: checked ? 'green' : 'white'}} >
<span>{name}</span>
<input ref = 'checkboxElement' type = 'checkbox'
onChange = {this.handleChange}
checked = {checked}/>
</div>
);
},
handleChange: function () {
const {name} = this.props;
const checked = $(this.refs.checkboxElement).is(':checked');
if (checked) {
checkboxListAction.check(name);
} else {
checkboxListAction.uncheck(name);
}
}
});
module.exports = CheckboxItem;

There are a few approaches you can take:
Don't render all 10,000 - just render the visible check boxes (+ a few more) based on panel size and scroll position, and handle scroll events to update the visible subset (use component state for this, rather than flux). You'll need to handle the scroll bar in some way, either by rendering one manually, or easier by using the normal browser scroll bar by adding huge empty divs at the top and bottom to replace the checkboxes you aren't rendering, so that the scroll bar sits at the correct position. This approach allows you to handle 100,000 checkboxes or even a million, and the first render is fast as well as updates. Probably the preferred solution. There are lots of examples of this kind of approach here: http://react.rocks/tag/InfiniteScroll
Micro-optimize - you could do storage.toArray().map(...) (so that you aren't creating an intermediate map), or even better, make and empty array and then do storage.forEach(...) adding the elements with push - much faster. But the React diffing algorithm is still going to have to diff 10000 elements, which is never going to be fast, however fast you make the code that generates the elements.
Split your huge Map into chunks in some way, so that only 1 chunk changes when you check a chechbox. Also split up the React components in the same way (into CheckboxListChunks) or similar. This way, you'll only need to re-render the changed chunk, as long as you have a PureComponent type componentShouldUpdate function for each chunk (possibly Reflux does this for you?).
Move away from ImmutableJS-based flux, so you have better control over what changes when (e.g. you don't have to update the parent checkbox map just because one of the children has changed).
Add a custom shouldComponentUpdate to CheckboxList:
shouldComponentUpdate:function(nextProps, nextState) {
var storage = this.state.storage;
var nextStorage = nextState.storage;
if (storage.size !== nextStorage.size) return true;
// check item names match for each index:
return !storage.keySeq().equals(nextStorage.keySeq());
}

Beyond the initial render, you can significantly increase rendering speed of large collections by using Mobservable. It avoids re-rendering the parent component that maps over the 10.000 items unnecessarily when a child changes by automatically applying side-ways loading. See this blog for an in-depth explanation.

Btw, I give up flux...
I finally decided to use mobservable to solve my problem.
I have made an example https://github.com/raymondsze/react-example
see the https://github.com/raymondsze/react-example/tree/master/src/mobservable for the coding.

Your render function looks somewhat more complicated then it needs to be:
it first generates an array of JSX components
then converts applies a (jQuery?) .toArray()
then returns this newly generated array.
Maybe simplifying your render function to something like this would help?
render: function () {
return (
<div className = 'checkbox-list'>
<div>
CheckBox List
</div>
<ul>
{this.state.storage.map((state, name) => {
return (
<li key = {name}>
<CheckboxItem name = {name} />
</li>
);
})}
</ul>
</div>
);
},

Do you really need to save the check status in you store every time check/uncheck?
I recently meet similar problem like you. Just save a checkedList array [name1,name2 ...] in the CheckboxList component's state, and change this checkedList every time you check/uncheck an item. When you want to save check status to data storage, call an Action.save() and pass the checkedList to store.
But if you really need to save to data storage every time check/uncheck, this solution won't help -_-.