React: can't update the state of Status, no re-render - reactjs

I have been working with react for a few weeks and have encountered a problem when trying to create a todo app. When I want to update the state of status in handleStatus(), nothing happens in the browser.
handleStatus(event) {
let newStatus;
const changeState = event.status == 'done' ? newStatus = 'open' : newStatus = 'done';
this.setState({ status: newStatus });
Why I can't update this state like I did with the others? Does anyone have a solution?
Thank you very much.
Here is the full code:
import React from "react";
import { InputBar } from "./InputBar";
import { Todo } from "./Todo";
const emptyForm = {
enterTodo: ""
};
export class TodoTable extends React.Component {
constructor(props) {
super(props);
this.state = {
enterTodo: "",
todos: this.props.todos,
status: 'open'
};
this.handleEnterTodo = this.handleEnterTodo.bind(this);
this.handleStatus = this.handleStatus.bind(this);
this.handleCreateTodo = this.handleCreateTodo.bind(this);
this.handleClearTodos = this.handleClearTodos.bind(this);
this.handleDeleteTodo = this.handleDeleteTodo.bind(this);
}
//Textbox Input handler
handleEnterTodo(event) {
this.setState({
enterTodo: event.target.value
});
}
//Status handler
handleStatus(event) {
let newStatus;
const changeState = event.status == 'done' ? newStatus = 'open' : newStatus = 'done';
this.setState({ status: newStatus });
}
//delete todo
handleDeleteTodo(event) {
let todo = this.state.todos;
todo.splice(this.state.todos.indexOf(event), 1)
this.setState({ todo });
}
//Create Todo
handleCreateTodo(event) {
const todo = {
id: this.state.todos.length,
describtion: this.state.enterTodo,
status: 'open'
};
this.setState({
todos: [todo, ...this.state.todos]
})
this.state.enterTodo = emptyForm.enterTodo; // Überarbeiten
}
//Clear Todo List
handleClearTodos(event) {
let CleanedTodos = []
this.state.todos.forEach((element, index) => {
if(this.state.todos[index].status == 'open'){
CleanedTodos.push(this.state.todos[index]);
}
});
this.setState({
todos: CleanedTodos
});
}
render() {
return (
<>
<InputBar
handleCreateTodo={ this.handleCreateTodo }
handleEnterTodo={ this.handleEnterTodo }
enterTodo={ this.state.enterTodo }
handleClearTodos={ this.handleClearTodos }
/>
<Todo
handleStatus={ this.handleStatus }
todos={ this.state.todos }
handleClearTodos={ this.state.handleClearTodos }
handleDeleteTodo= { this.handleDeleteTodo }
/>
</>
);
}
}

Remember if your are keeping the status of done in this component then all the todos in the todo table will show they are of the status done
the best way would be each todo having its own local state of done so that each done state is unique and then handle it something like this
<p value="heyy" onClick={(e) => console.log(e.target.getAttribute("value"))}>Something</p>
OR
const Todo = (props) => {
const [done, setDone] = useState(false)
return <p onclick={() => setDone(true)} >{todo}</p>
}
todos.map(todo => {
return <Todo />
})

Related

React - Render Key Press Event

I cannot seem to find a fitting example anywhere online. I have little experience with javaScript and React, and my issue might be trivial. The keypress event function works fine if run it by itself. However, if I try to implement it into the class app, and call the function from the render section I get this error: Error message. Any ideas? Thanks in advance. I have added the code.
import React, { Component, useEffect, useState } from 'react';
import './App.css';
import Spotify from 'spotify-web-api-js';
const spotifyWebApi = new Spotify();
class App extends Component {
constructor(){
super();
const params = this.getHashParams();
this.state = {
loggedIn: params.access_token ? true : false,
nowPlaying: {
name: 'Not Checked',
image: '',
device: '',
user_id: '',
playlists: []
}
}
if (params.access_token){
spotifyWebApi.setAccessToken(params.access_token)
}
};
useKeyPress(targetKey) {
const [keyPressed, setKeyPressed] = useState();
// Når du trykker på knappen - sætter vi keyPressed til true for at vise resultatet.
function downHandler({ key }) {
if (key === targetKey) {
this.setKeyPressed(true);
}
}
// Når du releaser knappen - sætter vi keyPressed til false for at fjerne resultatet igen.
const upHandler = ({ key }) => {
if (key === targetKey) {
this.setKeyPressed(false);
}
};
useEffect(() => {
window.addEventListener('keydown', downHandler);
window.addEventListener('keyup', upHandler);
// Det er altid "pænt" at ryde op efter sig selv, så vi fjerner eventListeners i return metoden
return () => {
window.removeEventListener('keydown', downHandler);
window.removeEventListener('keyup', upHandler);
};
}, []);
return this.keyPressed;
}
Fapp() {
const aPressed = this.useKeyPress('a');
const sPressed = this.useKeyPress('s');
const dPressed = this.useKeyPress('d');
const fPressed = this.useKeyPress('f');
return (
<div>
{ aPressed ? 'a' : 'not a'}
</div>
);
}
getHashParams() {
var hashParams = {};
var e, r = /([^&;=]+)=?([^&;]*)/g,
q = window.location.hash.substring(1);
while ( e = r.exec(q)) {
hashParams[e[1]] = decodeURIComponent(e[2]);
}
return hashParams;
}
getNowPlaying(){
spotifyWebApi.getMyCurrentPlaybackState()
.then((response) => {
this.setState({
nowPlaying: {
name: response.item.name,
image: response.item.album.images[0].url
}
}
)
})
}
handleKeyDown(event) {
if(event.keyCode === 13) {
console.log('Enter key pressed')
}
}
render() {
return (
<div className="App">
<a href='http://localhost:8888'>
<button>Login with Spotify</button>
</a>
<div> Now Playing: { this.state.nowPlaying.name } </div>
<div> user: { this.state.nowPlaying.user_id } </div>
<div>
<img src={ this.state.nowPlaying.image } style={{width: 100}}/>
</div>
<button onClick={() => this.getNowPlaying()}>
Check Now Playing
</button>
</div>
);
};
}
export default App;

I think render works twice

I'm only learning React, trying to write a simple TODO list app. When I'm trying to add a new task, two identical tasks are added. I tried to debug by the console.log element and saw a problem. render works twice, so my button sends info to the function twice. Can someone please guide me to the solution? Here is the code.
import React from 'react';
class TaskInput extends React.Component {
constructor(props) {
super(props);
this.state = {
input: ''
};
}
addTask = () => {
const { input } = this.state;
if (input) {
this.props.addTask(input);
this.setState({ input: '' });
}
};
handleEnter = event => {
if (event.key === 'Enter') this.addTask();
};
inputChange = event => {
this.setState({ input: event.target.value });
};
render() {
const { input } = this.state;
console.log(this.state);
return (
<div className="task-input">
<input
type="text"
onKeyPress={this.handleEnter}
onChange={this.inputChange}
value={input}
></input>
<button onClick={this.addTask } >ADD</button>
</div>
);
}
}
export default TaskInput;
Here is the App.js code:
import React from 'react';
import Task from './components/Task';
import TaskInput from './components/TaskInput';
class App extends React.Component {
constructor () {
super();
this.state = {
tasks: [
{id: 0, title: 'Create Todo-app', done: false},
{id: 1, title: 'Do smth else', done: true},
{id: 2, title: 'Do more things', done: false}
]
};
}
addTask = task => {
this.setState(state => {
let {tasks} = state;
console.log("state");
tasks.push({
id: tasks.length !==0 ? tasks.length : 0,
title: task,
done: false
});
return tasks;
});
}
doneTask = id => {
const index = this.state.tasks.map(task => task.id).indexOf(id);
this.setState(state => {
let {tasks} = state;
tasks[index].done = true;
return tasks;
});
};
deleteTask = id => {
const index = this.state.tasks.map(task => task.id).indexOf(id);
this.setState(state => {
let {tasks} = state;
delete tasks[index];
return tasks;
})
};
render() {
const { tasks } = this.state;
const activeTasks = tasks.filter(task => !task.done);
const doneTasks = tasks.filter(task => task.done)
return (
<div className = "App">
<h1 className="top">Active tasks: {activeTasks.length}</h1>
{[...activeTasks, ...doneTasks].map(task => (
<Task
doneTask={() => this.doneTask(task.id)}
deleteTask={() => this.deleteTask(task.id)}
task={task}
key={task.id}
></Task>))}
<TaskInput addTask={this.addTask}></TaskInput>
</div>
);
}
}
export default App;
I think you are accidentally directly modifying the state inside addTask.
The line let {tasks} = state; is creating a reference to the original state, rather than a new copy, and then your push modifies the state directly.
Using expansion/spread syntax to get a copy of your array like this should work:
addTask = task => {
this.setState(state => {
const tasks = [ ...state.tasks ];
tasks.push({
id: tasks.length !==0 ? tasks.length : 0,
title: task,
done: false
});
return { tasks };
});
}
Using let tasks = [ ...state.tasks ]; will create a new array rather than a reference, and prevent the state from being modified directly.
The reason you were seeing double results was that you effectively set the state with the push, and then set it again with the returned value.
I've changed your code a little bit. It's working here. Would you please check?
class TaskInput extends React.Component {
constructor(props) {
super(props);
this.state = {
input: "",
tasks: []
};
}
addTask = newTask => {
this.setState(state => ({
...state,
input: "",
tasks: [...state.tasks, newTask]
}));
};
handleEnter = event => {
if (event.key === "Enter") this.addTask(event.target.value);
};
inputChange = event => {
this.setState({ input: event.target.value });
};
render() {
const { input } = this.state;
console.log(this.state);
return (
<div className="task-input">
<input
onKeyPress={this.handleEnter}
onChange={this.inputChange}
value={input}
></input>
<button onClick={this.addTask}>ADD</button>
</div>
);
}
}
ReactDOM.render(<TaskInput/>, document.querySelector("#root"));
.as-console-wrapper {
max-height: 5px;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id="root"></div>

React App Rendering Before Firestore Data Has Loaded

I am trying to load data from Firestore and show it in the gantt-chart, but it renders before it has loaded the data from firebase. So I call setState inside of componentDidMount because I thought this would then call the render again at which point the data would be there. But it is still sitting empty. Any ideas as to why?
import React, { Component } from 'react';
import Gantt from './Gantt';
import Toolbar from './Toolbar';
import MessageArea from './MessageArea';
import Firebase from './Firebase';
import './App.css';
class App extends Component {
constructor(props) {
super(props);
this.state = {
currentZoom: 'Days',
messages: [],
projects: [],
links: []
};
this.handleZoomChange = this.handleZoomChange.bind(this);
this.logTaskUpdate = this.logTaskUpdate.bind(this);
this.logLinkUpdate = this.logLinkUpdate.bind(this);
}
componentDidMount() {
const db = Firebase.firestore();
var projectsArr = [];
db.collection('projects').get().then((snapshot) => {
snapshot.docs.forEach(doc => {
let project = doc.data();
projectsArr.push({id: 1, text: project.name, start_date: '15-04-2017', duration: 3, progress: 0.6});
});
});
this.setState({
projects: projectsArr
});
}
addMessage(message) {
var messages = this.state.messages.slice();
var prevKey = messages.length ? messages[0].key: 0;
messages.unshift({key: prevKey + 1, message});
if(messages.length > 40){
messages.pop();
}
this.setState({messages});
}
logTaskUpdate(id, mode, task) {
let text = task && task.text ? ` (${task.text})`: '';
let message = `Task ${mode}: ${id} ${text}`;
this.addMessage(message);
}
logLinkUpdate(id, mode, link) {
let message = `Link ${mode}: ${id}`;
if (link) {
message += ` ( source: ${link.source}, target: ${link.target} )`;
}
this.addMessage(message)
}
handleZoomChange(zoom) {
this.setState({
currentZoom: zoom
});
}
render() {
var projectData = {data: this.state.projects, links: this.state.links};
return (
<div>
<Toolbar
zoom={this.state.currentZoom}
onZoomChange={this.handleZoomChange}
/>
<div className="gantt-container">
<Gantt
tasks={projectData}
zoom={this.state.currentZoom}
onTaskUpdated={this.logTaskUpdate}
onLinkUpdated={this.logLinkUpdate}
/>
</div>
<MessageArea
messages={this.state.messages}
/>
</div>
);
}
}
export default App;
You are calling setState outside of the then callback.
So Change
db.collection('projects').get().then((snapshot) => {
snapshot.docs.forEach(doc => {
let project = doc.data();
projectsArr.push({id: 1, text: project.name, start_date: '15-04-2017', duration: 3, progress: 0.6});
});
});
this.setState({
projects: projectsArr
});
To
db.collection('projects').get().then((snapshot) => {
snapshot.docs.forEach(doc => {
let project = doc.data();
projectsArr.push({id: 1, text: project.name, start_date: '15-04-2017', duration: 3, progress: 0.6});
});
this.setState({
projects: projectsArr
});
});
Also, as a general pattern you can do something like this:
class AsyncLoad extends React.Component {
state = { data: null }
componentDidMount () {
setTimeout(() => {
this.setState({ data: [1, 2, 3]})
}, 3000)
}
render () {
const { data } = this.state
if (!data) { return <div>Loading...</div> }
return (
<pre>{JSON.stringify(data, null, 4)}</pre>
)
}
}
It's a common enough operation to create an HOC for it.

How to rerender one sibling component due to change of second sibling component

I have this structure:
<Filter>
<Departure setDeparture={this.setDeparture} />
<Destination setDestination={this.setDestination} iataDeparture={this.state.departure} />
<DatePicker setDates={this.setDates} />
<SearchButton />
</Filter>
Now, I try to rerender Destination component when I update Departure component. Unfortunatelly my code doesn't work.
I don't use redux because I don't know it yet, so I try solutions without redux.
Please, help me with this problem.
Here goes code for each component:
Filter:
import React, { Component } from 'react';
import axios from 'axios';
import Departure from './Departure';
import Destination from './Destination';
import DatePicker from './DatePicker';
import SearchButton from './SearchButton';
class Filter extends Component {
constructor(props) {
super(props);
this.state = {
departure: '',
destination: '',
startDate: '',
endDate: '',
flights: []
}
}
handleSubmit = event => {
const getFlights = `https://murmuring-ocean-10826.herokuapp.com/en/api/2/flights/from/${this.state.departure}/to/${this.state.destination}/${this.state.startDate}/${this.state.endDate}/250/unique/?limit=15&offset-0`;
event.preventDefault();
console.log(this.state.departure);
console.log(this.state.destination);
console.log(this.state.startDate);
console.log(this.state.endDate);
axios.get(getFlights)
.then(response => {
this.setState({ flights: response.data.flights });
console.log(getFlights);
console.log(this.state.flights);
this.props.passFlights(this.state.flights);
});
}
setDeparture = departure => {
this.setState({ departure: departure });
}
setDestination = destination => {
this.setState({ destination: destination });
}
setDates = (range) => {
this.setState({
startDate: range[0],
endDate: range[1]
});
}
render() {
return (
<section className='filter'>
<form className='filter__form' onSubmit={this.handleSubmit}>
<Departure setDeparture={this.setDeparture} />
<Destination setDestination={this.setDestination} iataDeparture={this.state.departure} />
<DatePicker setDates={this.setDates} />
<SearchButton />
</form>
</section>
);
}
}
export default Filter;
Departure:
import React, { Component } from 'react';
import axios from 'axios';
const url = 'https://murmuring-ocean-10826.herokuapp.com/en/api/2/forms/flight-booking-selector/';
class Departure extends Component {
constructor(props) {
super(props);
this.state = {
airports: [],
value: '',
iataCode: ''
}
}
componentDidMount() {
axios.get(url)
.then(data => {
const airports = data.data.airports;
const updatedAirports = [];
airports.map(airport => {
const singleAirport = [];
singleAirport.push(airport.name);
singleAirport.push(airport.iataCode);
updatedAirports.push(singleAirport);
return singleAirport;
});
this.setState({
airports: updatedAirports,
value: airports[0].name,
iataCode: airports[0].iataCode
});
this.props.setDeparture(this.state.iataCode);
});
}
handleChange = event => {
const nameValue = event.target.value;
const iataCode = this.state.airports.find(airport => {
return airport[0] === nameValue;
});
this.setState({
value: event.target.value,
iataCode: iataCode[1]
});
this.props.setDeparture(iataCode[1]);
}
render() {
const departureNames = this.state.airports;
let departureOptions = departureNames.map((item, index) => {
return (
<option value={item[0]} key={index}>{item[0]}</option>
);
});
return (
<div className='filter__form__select'>
<select value={this.state.value} onChange={this.handleChange}>
{departureOptions}
</select>
</div>
);
}
}
export default Departure;
Destination:
import React, { Component } from 'react';
import axios from 'axios';
const url = 'https://murmuring-ocean-10826.herokuapp.com/en/api/2/forms/flight-booking-selector/';
class Destination extends Component {
constructor(props) {
super(props);
this.state = {
routes: {},
airports: [],
value: '',
iataCode: '',
iataDestinationAirports: '',
options: []
}
}
componentDidMount() {
axios.get(url)
.then(data => {
const routes = data.data.routes;
const airports = data.data.airports;
const updatedAirports = [];
airports.map(airport => {
const singleAirport = [];
singleAirport.push(airport.name);
singleAirport.push(airport.iataCode);
updatedAirports.push(singleAirport);
return singleAirport;
});
this.setState({
routes: routes,
airports: updatedAirports,
});
})
.then(() => {
this.getNamesFromIataCode();
this.props.setDestination(this.state.iataDestinationAirports);
});
}
componentDidUpdate(prevProps) {
if (this.props.iataDeparture !== prevProps.iataDeparture) {
this.setState({ iataCode: this.props.iataDeparture });
() => this.getNamesFromIataCode();
};
}
handleChange = (event) => {
const nameValue = event.target.value;
const iataCode = this.state.airports.find(airport => {
return airport[0] === nameValue;
});
this.setState({
value: event.target.value,
iataDestinationAirports: iataCode[1]
});
this.props.setDestination(iataCode[1]);
}
getNamesFromIataCode = () => {
const iataCode = this.state.iataCode;
console.log(iataCode);
const destinationNames = this.state.routes[iataCode];
let destionationAirports = destinationNames.map(item => {
return this.state.airports.filter(el => {
return el[1] === item;
});
});
let arrayOfOptions = [];
let firstOptionIataCode = '';
let firstOptionName = '';
let destinationOptions = destionationAirports.map((item, index) => {
console.log(item);
arrayOfOptions.push(item[0]);
return (
<option value={item[0][0]} key={index}>{item[0][0]}</option>
);
});
firstOptionIataCode = arrayOfOptions[0][1];
firstOptionName = arrayOfOptions[0][0];
console.log(firstOptionIataCode);
this.setState({
options: destinationOptions,
iataDestinationAirports: firstOptionIataCode,
value: firstOptionName
});
console.log(this.state.iataDestinationAirports);
console.log(this.state.options);
return destinationOptions;
}
render() {
const selectionOptions = this.state.options;
return (
<div className='filter__form__select'>
<select value={this.state.value} onChange={this.handleChange}>
{selectionOptions}
</select>
</div>
);
}
}
export default Destination;
As Tholle mentioned, you need to lift the state up. Here's an example:
import React from "react";
import ReactDOM from "react-dom";
const A = ({ users, selectUser }) => {
return (
<React.Fragment>
<h1>I am A.</h1>
{users.map((u, i) => {
return <button onClick={() => selectUser(i)}>{u}</button>;
})}
</React.Fragment>
);
};
const B = ({ user }) => {
return <h1>I am B. Current user: {user}</h1>;
};
const C = ({ user }) => {
return <h1>I am C. Current user: {user}</h1>;
};
class App extends React.Component {
state = {
users: ["bob", "anne", "mary"],
currentUserIndex: 0
};
selectUser = n => {
this.setState({
currentUserIndex: n
});
};
render() {
const { users, currentUserIndex } = this.state;
const currentUser = users[currentUserIndex];
return (
<React.Fragment>
<A selectUser={this.selectUser} users={users} />
<B user={currentUser} />
<C user={currentUser} />
</React.Fragment>
);
}
}
const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);
Working example here.

Assigning state to props from redux does not work

import React, { Component } from 'react';
import DisplayTable from './Table.js';
class App extends Component {
constructor(props) {
super(props);
this.state = {
menuItems: this.props.menu_items,
searchString: '',
displayItems: this.props.menu_items
}
this.search = this.search.bind(this);
this.handleChange = this.handleChange.bind(this);
}
componentWillMount() {
this.props.get_menu_items_api(false);
}
componentWillReceiveProps(nextProps) {
this.setState({ menuItems: nextProps.menu_items })
}
handleChange(e, isEnter) {
const searchData = () => {
let tempMenuProductDetails = this.props.menu_items;
const filterArray = tempMenuProductDetails.reduce((result, category) => {
if (category.categoryName.toLowerCase()
.indexOf(this.state.searchString.toLowerCase()) > -1) {
result.push(category);
}
if (category.productList && category.productList.length > 0) {
category.productList = category.productList.reduce((productListResult,
productList) => {
if (!!productList.productName &&
productList.productName.toLowerCase()
.indexOf(this.state.searchString.toLowerCase()) > -1)
{
productListResult.push(productList);
}
return productListResult;
}, []);
}
return result;
}, []);
this.setState({
displayItems: filterArray
}, function () {
console.log(this.state.displayItems);
})
console.log(filterArray);
}
if (!isEnter) {
this.setState({
searchString: e.target.value
});
} else {
searchData();
}
}
search(e) {
if (e.keyCode == 13) {
this.handleChange(e, true);
}
this.handleChange(e, false);
}
render() {
console.log(this.state.displayItems);
console.log(this.props.menu_items);
console.log(this.state.menuItems);
return (
<DisplayTable dataProp={this.state.displayItems} editFuncProp=
{this.props.edit_menu_items_api} /> )
}
}
export default App;
I have this search function in this file that does not update the value of props coming from the container of redux. Now when I pass {this.state.displayItems} in menu ,it does not display the data.
But when I pass {this.props.menu_items} it displays the data and I am not able to modify this.props.menu_items on the basis of search.
I have tried this code . what should i do?
The problem seems to be that, initially this.props.menu_items is an empty array and only after some API call the value is updated and you get the returned array on the second render, thus if you use it like
<DisplayTable dataProp={this.props.menu_items} editFuncProp=
{this.props.edit_menu_items_api} />
it works. Now that you use
<DisplayTable dataProp={this.state.displayItems} editFuncProp=
{this.props.edit_menu_items_api} />
and displayItems is only initialized in the constructor which is only executed once at the time, component is mounted and hence nothing is getting displayed.
The solution seems to be that you update the displayItems state in componentWillReceiveProps and call the search function again with the current search string so that you search results are getting updated.
Code:
import React, { Component } from 'react';
import DisplayTable from './Table.js';
class App extends Component {
constructor(props) {
super(props);
this.state = {
menuItems: this.props.menu_items,
searchString: '',
displayItems: this.props.menu_items
}
this.search = this.search.bind(this);
this.handleChange = this.handleChange.bind(this);
}
componentWillMount() {
this.props.get_menu_items_api(false);
}
componentWillReceiveProps(nextProps) {
this.setState({ menuItems: nextProps.menu_items, displayItems: nextProps.menu_items })
this.handleChange(null, true);
}
handleChange(e, isEnter) {
const searchData = () => {
let tempMenuProductDetails = this.props.menu_items;
const filterArray = tempMenuProductDetails.reduce((result, category) => {
if (category.categoryName.toLowerCase()
.indexOf(this.state.searchString.toLowerCase()) > -1) {
result.push(category);
}
if (category.productList && category.productList.length > 0) {
category.productList = category.productList.reduce((productListResult,
productList) => {
if (!!productList.productName &&
productList.productName.toLowerCase()
.indexOf(this.state.searchString.toLowerCase()) > -1)
{
productListResult.push(productList);
}
return productListResult;
}, []);
}
return result;
}, []);
this.setState({
displayItems: filterArray
}, function () {
console.log(this.state.displayItems);
})
console.log(filterArray);
}
if (!isEnter) {
this.setState({
searchString: e.target.value
});
} else {
searchData();
}
}
search(e) {
if (e.keyCode == 13) {
this.handleChange(e, true);
}
this.handleChange(e, false);
}
render() {
console.log(this.state.displayItems);
console.log(this.props.menu_items);
console.log(this.state.menuItems);
return (
<DisplayTable dataProp={this.state.displayItems} editFuncProp=
{this.props.edit_menu_items_api} /> )
}
}
export default App;

Resources