I'm only trying to deal with the React, so my question may seem very simple, but still I'm stuck on it.
I have two blocks (div.user-data__row) in which there are some values. I change the state of the component (handleChange function), the state in which these blocks are replaced by text fields (textarea.text), and I want when I click on the save button and call saveChange function, the value from each text field is taken and passed to the blocks (1st textarea to 1st block, etc).
I found examples of solving a similar case using the ref attribute, but later read that this is no longer an actual solution and so no one does. Please help me find the actual implementation path.
class UserData extends React.Component {
constructor(props) {
super(props);
this.state = {
edit: true,
};
this.handleChange = this.handleChange.bind(this);
this.saveChange = this.handleChange.bind(this);
}
handleChange() {
this.setState(() => ({
edit: !this.state.edit,
}));
}
saveChange() {
this.setState(() => ({
edit: false
}))
}
render() {
if (this.state.edit) {
return (
<div className="user-data">
<div className="user-data__row">{this.props.userData.name}</div>
<div className="user-data__row">{this.props.userData.email}</div>
<button onClick={ this.handleChange }>Edit</button>
</div>
);
} else {
return (
<div className="user-data">
<textarea className="text" defaultValue={this.props.userData.name}></textarea>
<textarea className="text" defaultValue={this.props.userData.email}></textarea>
<button onClick={ this.saveChange }>Save</button>
</div>
)
}
}
}
Because props are read-only & because userData (email+name) can be changed inside the component , you have to populate props values in the state, then manage the state after that will be enough.
Also , you will need to convert your textarea from uncontrolled component to controlled component by:
Using value instead of defaultValue
Implementing onChange with setState of that value as handler .
Value of textarea should be read from state not props.
If props of <UserData /> may be updated from outside throughout its lifecycle , you will need componentWillReceiveProps later on.
Also you have a typo if (!this.state.edit) { and not if (this.state.edit) { .
class UserData extends React.Component {
state = {
edit: true,
userDataName: this.props.userData.name, // Populate props values
userDataEmail: this.props.userData.email, // Populate props values
};
handleChange = () => {
this.setState((state) => ({
edit: !state.edit,
}));
}
saveChange =() => {
this.setState(() => ({
edit: false
}))
}
render() {
if (!this.state.edit) {
return (
<div className="user-data">
<div className="user-data__row">{this.state.userDataName}</div>
<div className="user-data__row">{this.state.userDataEmail}</div>
<button onClick={ this.handleChange }>Edit</button>
</div>
);
} else {
return (
<div className="user-data">
<textarea className="text" value={this.state.userDataName} onChange={(e) => this.setState({userDataName: e.target.value})}></textarea>
<textarea className="text" value={this.state.userDataEmail} onChange={(e) => this.setState({userDataEmail: e.target.value})}></textarea>
<button onClick={ this.saveChange }>Save</button>
</div>
)
}
}
}
ReactDOM.render(<UserData userData={{name: 'Abdennoor', email: 'abc#mail.com'}} /> , document.querySelector('.app'))
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div class="app" />
You're receiving values for <div> from this.props, it means that these values should came from some external source and passed to your component. A way of passing these values to component's props is out of scope of this question, it can be implemented in a very different ways. Usually it came either from parent component or from some connected store.
You need to obtain values from your <textarea> form fields, it can be done directly (using ref) or by using some third-party library that provides form handling. Then these values needs to be stored (and obtained) either directly from component's state or from external source (via props).
Unfortunately scope of your question is too broad to be able to give more precise answer, but hope that this information will lead you to some kind of solution.
You can also use contentEditable, which it will allow you to edit the content of the div.
class UserData extends React.Component {
constructor(props) {
super(props);
this.state = {
edit: true
};
this.handleChange = this.handleChange.bind(this);
}
handleChange() {
this.setState(() => ({
edit: !this.state.edit
}));
}
render() {
const { edit } = this.state;
return (
<div className="user-data">
<div className="user-data__row" contentEditable={edit}>{this.props.userData.name}</div>
<div className="user-data__row" contentEditable={edit}>{this.props.userData.email}</div>
<button onClick={this.handleChange}>
{edit ? Save : Edit}
</button>
</div>
)
}
}
Related
I am trying to build a ToDoList app and I have two components. I have a main component that handles the state and another button component that renders a delete button next to every task that I render. The problem I have is that i cant seem to connect the delete button to the index of the array and delete that specific item in the array by clicking on the button next to it.
I have tried to connect the index by using the map key id to the delete function.
just need help with how my delete function should look like and how its going to get the index of the item that is next to it and delete it.
class App extends React.Component {
constructor(props) {
super(props);
this.state = {
userInput: '',
toDoList : []
}
this.handleSubmit = this.handleSubmit.bind(this);
this.handleChange = this.handleChange.bind(this);
this.delete = this.delete.bind(this);
}
handleSubmit() {
const itemsArray = this.state.userInput.split(',');
this.setState({
toDoList: this.state.toDoList.concat(itemsArray),
userInput: ''
});
}
handleChange(e) {
this.setState({
userInput: e.target.value
});
}
delete(id) {
this.setState({
toDoList: this.state.toDoList.filter( (item) => id !== item.id )
})
}
render() {
return (
<div>
<textarea
onChange={this.handleChange}
value={this.state.userInput}
placeholder="Separate Items With Commas" /><br />
<button onClick={this.handleSubmit}>Create List</button>
<h1>My Daily To Do List:</h1>
<Button toDoList={this.state.toDoList} handleDelete={this.delete} />
</div>
);
}
};
class Button extends React.Component {
constructor(props) {
super(props);
}
render() {
return (
<ul>
{
this.props.toDoList.map( (item) => <li key={item.id}>{item.text} <button onClick={this.props.delete(item.id)}>Done!</button></li> )
}
</ul>
);
}
};
I reviewed your edited code and made a couple of changes.
I don’t get what exactly you want to achieve with you handleSubmit method but items it adds to the list are simple strings and don’t have neither ‘id’ nor ‘text’ properties you’re referring to in other places. Possibly you’re going to change this later but while your to do items are just strings I’ve edited your code so that it work properly under this condition.
Edited delete method now accepts not item.id as a parameter but the whole item object. Yet I'm using functional form of setState as it was correctly suggested by #Hamoghamdi
delete(itemToDelete) {
this.setState(state => ({
toDoList: state.toDoList.filter( (item) => itemToDelete !== item)
}))
}
Edited render method of Button class now displays items as text and properly bind delete handler...
render() {
return (
<ul>
{
this.props.toDoList.map( (item) => <li key={item}>
{item}
<button onClick={() => this.props.handleDelete(item)}>Done!</button>
</li> )
}
</ul>
);
}
BTW Button is a bad naming for the component that isn’t exactly a button. Yet it’s better to implement it as a functional component. Use class components only if the component has its own state.
you should try using an anonymous function with setState() instead of returning an object literal directly, specially when you want to do something affected by the previous or current state
using this.state inside of setState() won't give you any good results.
here, try this:
delete = (id) => {
this.setState((prevState) => {
return { toDoList: prevState.filter( (task) => id !== task.id )}
});
You need to bind the method in constructor for example:
constructor(props) {
//...
this.handleDelete = this.handleDelete.bind(this)
}
also you can find another ways how to bind methods
In terms of handling the deleting the items, you can use
handleDelete(index) {
// Use the splice array function: splice(index, deleteCount)
this.todoList.splice(index, 1);
}
And that is all that easy
I recently got started with React and want to build a little application to fetch weather data. My API has a function to return autocomplete suggestions. So when my autosuggestion array is not empty I render a list and upon clicking one of the <li>'s I want the value inside of the input box. I manage to set the state of my SearchBar but can't change it's value.
Edit: I try to get my value from changeState() into my <input type="text" placeholder="City, Zip Code, Coordinates" onChange={evt => this.updateInputValue(evt)} />. I can search for terms otherwise.
import React from 'react';
import './SearchBar.css';
import Suggestion from './Suggestion';
class SearchBar extends React.Component{
constructor(props) {
super(props);
this.state = {inputValue: ''};
this.search = this.search.bind(this);
this.updateInputValue = this.updateInputValue.bind(this);
this.handleKeyPress = this.handleKeyPress.bind(this);
this.changeState = this.changeState.bind(this);
}
changeState(value) {
console.log(value);
// Logs value of text between <li></li>
this.setState({inputValue: value});
}
search() {
this.props.onSearch(this.state.inputValue);
}
updateInputValue(evt) {
this.setState({
inputValue: evt.target.value
});
this.props.onChange(this.state.inputValue);
}
handleKeyPress(e) {
if(e.key === 'Enter') {
this.search();
}
}
render() {
return (
<div>
<div className="SearchGroup" onKeyPress={this.handleKeyPress} >
<input type="text" placeholder="City, Zip Code, Coordinates" onChange={evt => this.updateInputValue(evt)} />
<a onClick={this.search}>Go</a>
</div>
<Suggestion autocomplete={this.props.autocomplete} onSelect={this.changeState} />
</div>
);
}
}
export default SearchBar;
For the sake of completeness my Suggestion.js:
import React from 'react';
import './Suggestion.css';
class Suggestion extends React.Component{
constructor(props) {
super(props);
this.updateInputField = this.updateInputField.bind(this);
}
updateInputField(evt) {
this.props.onSelect(evt.currentTarget.innerText);
}
render(){
if(this.props.autocomplete && this.props.autocomplete.length > 0) {
return (
<div className="Suggestion">
<ul>
{
this.props.autocomplete.map((location) => {
return (
<li key={location.id} onClick={this.updateInputField}>{location.name}</li>
)
})
}
</ul>
</div>
);
} else {
return <div className="None"></div>
}
}
}
export default Suggestion;
I would also prefer to submit location.url in Suggestion, but I could not find a property that matches inside of evt.
As mentioned in my comment. You are setting state and immediately passing state to onChange function in updateInputValue event handler function which is not correct. Because you won't get the state value updated immediately, the state value updates only when it renders so, pass evt.target.value directly like below
updateInputValue(evt) {
this.setState({ inputValue: evt.target.value });
this.props.onChange(evt.target.value);
}
In order to see chnaged value on your input field, you have to pass value prop to input tag like below
<input type="text" placeholder="City, Zip Code, Coordinates" onChange={evt => this.updateInputValue(evt)} value={this.state.inputValue}/>
I would guess that you are trying to use value from state that isnt there yet, because setState is asynchronous
so either use callback on setState
updateInputValue(evt) {
this.setState({
inputValue: evt.target.value
}, ()=> this.props.onChange(this.state.inputValue));
}
or, use the value from event directly
updateInputValue(evt) {
const value = evt.target.value
this.setState({
inputValue: value
});
this.props.onChange(value)
}
plus you havent assigned value back to your input:
<input type="text" placeholder="City, Zip Code, Coordinates" onChange={evt => this.updateInputValue(evt)} value={this.state.inputValue}/>
The React setState doesn't update the state immediately. It puts it in the queue and updates the state in batches. if you want to access the updated state write the code in the setState callBack
this.setState({ inputValue: evt.target.value},()=> this.props.onChange(this.state.inputValue));
something like this
I'm having problems trying to render two react elements inside a react component after a onClick event. Wondering if that's even possible? I'm sure I'm messing up the ternary operator, but I cannot think on another way to do what I'm trying to do ?
TL;DR: "When I click a button I see elementA and elementB"
Here is a snippet of the code:
import React, { Component } from 'react';
class MyComponent extends Component {
constructor(props) {
super(props)
this.state = { showElement: true };
this.onHandleClick = this.onHandleClick.bind(this);
}
onHandleClick() {
console.log(`current state: ${this.state.showElement} and prevState: ${this.prevState}`);
this.setState(prevState => ({ showElement: !this.state.showElement }) );
};
elementA() {
<div>
<h1>
some data
</h1>
</div>
}
elementB() {
<div>
<h1>
some data
</h1>
</div>
}
render() {
return (
<section>
<button onClick={ this.onHandleClick } showElement={this.state.showElement === true}>
</button>
{ this.state.showElement
?
null
:
this.elementA() && this.elementB()
}
</section>
)
}
}
export default MyComponent;
You just inattentive.
elementA() {
return ( // You forget
<div>
<h1>
some data
</h1>
</div>
)
}
And the same in element B.
And if You want to see both components you should change Your ternary to
{ this.state.showElement
?
<div> {this.elementA()} {this.elementB()}</div>
:
null
}
Another "and", for toggling showElement in state just enough
this.setState({showElement: !this.state.showElement });
Try this instead, (I will add comments into the code trying to explain what's going on):
function SomeComponentName() { // use props if you want to pass some data to this component. Meaning that if you can keep it stateless do so.
return (
<div>
<h1>
some data
</h1>
</div>
);
}
class MyComponent extends Component {
constructor(props) {
super(props)
this.state = { showElement: false }; // you say that initially you don't want to show it, right? So let's set it to false :)
this.onHandleClick = this.onHandleClick.bind(this);
}
onHandleClick() {
this.setState(prevState => ({ showElement: !prevState.showElement }) );
// As I pointed out in the comment: when using the "reducer" version of `setState` you should use the parameter that's provided to you with the previous state, try never using the word `this` inside a "reducer" `setState` function
};
render() {
return (
<section>
<button onClick={ this.onHandleClick } showElement={this.state.showElement === false}>
</button>
{ this.state.showElement
? [<SomeComponentName key="firstOne" />, <SomeComponentName key="secondOne" />]
: null
}
</section>
)
}
}
export default MyComponent;
I'm teaching myself react with a super simple app that asks the user to type a word presented in the UI. If user enters it correctly, the app shows another word, and so on.
I've got it almost working, except for one thing: after a word is entered correctly, I need to clear the input element. I've seen several answers here about how an input element can clear itself, but I need to clear it from the component that contains it, because that's where the input is checked...
// the app
class AppComponent extends React.Component {
constructor() {
super();
this.state = {
words: ['alpha', 'bravo', 'charlie'],
index: 0
};
}
renderWordsource() {
const word = this.state.words[this.state.index];
return <WordsourceComponent value={ word } />;
}
renderWordinput() {
return <WordinputComponent id={1} onChange={ this.onChange.bind(this) }/>;
}
onChange(id, value) {
const word = this.state.words[this.state.index];
if (word == value) {
alert('yes');
var nextIndex = (this.state.index == this.state.words.count-1)? 0 : this.state.index+1;
this.setState({ words:this.state.words, index:nextIndex });
}
}
render() {
return (
<div className="index">
<div>{this.renderWordsource()}</div>
<div>{this.renderWordinput()}</div>
</div>
);
}
}
// the input component
class WordinputComponent extends React.Component {
constructor(props) {
this.state = { text:''}
}
handleChange(event) {
var text = event.target.value;
this.props.onChange(this.props.id, text);
}
render() {
return (
<div className="wordinput-component">
<input type="text" onChange={this.handleChange.bind(this)} />
</div>
);
}
}
See where it says alert('yes')? That's where I think I should clear the value, but that doesn't make any sense because it's a parameter, not really the state of the component. Should I have the component pass itself to the change function? Maybe then I could alter it's state, but that sounds like a bad idea design-wise.
The 2 common ways of doing this is controlling the value through state in the parent or using a ref to clear the value. Added examples of both
The first one is using a ref and putting a function in the child component to clear
The second one is using state of the parent component and a controlled input field to clear it
class ParentComponent1 extends React.Component {
state = {
input2Value: ''
}
clearInput1() {
this.input1.clear();
}
clearInput2() {
this.setState({
input2Value: ''
});
}
handleInput2Change(evt) {
this.setState({
input2Value: evt.target.value
});
}
render() {
return (
<div>
<ChildComponent1 ref={input1 => this.input1 = input1}/>
<button onClick={this.clearInput1.bind(this)}>Clear</button>
<ChildComponent2 value={this.state.input2Value} onChange={this.handleInput2Change.bind(this)}/>
<button onClick={this.clearInput2.bind(this)}>Clear</button>
</div>
);
}
}
class ChildComponent1 extends React.Component {
clear() {
this.input.value = '';
}
render() {
return (
<input ref={input => this.input = input} />
);
}
}
class ChildComponent2 extends React.Component {
render() {
return (
<input value={this.props.value} onChange={this.props.onChange} />
);
}
}
ReactDOM.render(<ParentComponent1 />, document.body);
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
I had a similar issue: I wanted to clear a form which contained multiple fields.
While the two solutions by #noveyak are working fine, I want to share a different idea, which gives me the ability to partition the responsibility between parent and child: parent knows when to clear the form, and the items know how to react to that, without using refs.
The idea is to use a revision counter which gets incremented each time Clear is pressed and to react to changes of this counter in children.
In the example below there are three quite simple children reacting to the Clear button.
class ParentComponent extends React.Component {
state = {revision: 0}
clearInput = () => {
this.setState((prev) => ({revision: prev.revision+1}))
}
render() {
return (
<div>
<ChildComponent revision={this.state.revision}/>
<ChildComponent revision={this.state.revision}/>
<ChildComponent revision={this.state.revision}/>
<button onClick={this.clearInput.bind(this)}>Clear</button>
</div>
);
}
}
class ChildComponent extends React.Component {
state = {value: ''}
componentWillReceiveProps(nextProps){
if(this.props.revision != nextProps.revision){
this.setState({value : ''});
}
}
saveValue = (event) => {
this.setState({value: event.target.value})
}
render() {
return (
<input value={this.state.value} onChange={this.saveValue} />
);
}
}
ReactDOM.render(<ParentComponent />, document.body);
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
EDIT:
I've just stumbled upon this beautifully simple solution with key which is somewhat similar in spirit (you can pass parents's revision as child's key)
Very very very simple solution to clear form is add unique key in div under which you want to render form from your child component key={new Date().getTime()}:
render(){
return(
<div className="form_first_step fields_black" key={new Date().getTime()}>
<Form
className="first_step">
// form fields coming from child component
<AddressInfo />
</div>
</Form>
</div>
)
}
Is it possible to focus div (or any other elements) using the focus() method?
I've set a tabIndex to a div element:
<div ref="dropdown" tabIndex="1"></div>
And I can see it gets focused when I click on it, however, I'm trying to dynamically focus the element like this:
setActive(state) {
ReactDOM.findDOMNode(this.refs.dropdown).focus();
}
Or like this:
this.refs.dropdown.focus();
But the component doesn't get focus when the event is triggered. How can I do this? Is there any other (not input) element I can use for this?
EDIT:
Well, It seems this it actually possible to do: https://jsfiddle.net/69z2wepo/54201/
But it is not working for me, this is my full code:
class ColorPicker extends React.Component {
constructor(props) {
super(props);
this.state = {
active: false,
value: ""
};
}
selectItem(color) {
this.setState({ value: color, active: false });
}
setActive(state) {
this.setState({ active: state });
this.refs.dropdown.focus();
}
render() {
const { colors, styles, inputName } = this.props;
const pickerClasses = classNames('colorpicker-dropdown', { 'active': this.state.active });
const colorFields = colors.map((color, index) => {
const colorClasses = classNames('colorpicker-item', [`colorpicker-item-${color}`]);
return (
<div onClick={() => { this.selectItem(color) }} key={index} className="colorpicker-item-container">
<div className={colorClasses}></div>
</div>
);
});
return (
<div className="colorpicker">
<input type="text" className={styles} name={inputName} ref="component" value={this.state.value} onFocus={() => { this.setActive(true) }} />
<div onBlur={() => this.setActive(false) } onFocus={() => console.log('focus')} tabIndex="1" ref="dropdown" className={pickerClasses}>
{colorFields}
</div>
</div>
);
}
}
React redraws the component every time you set the state, meaning that the component loses focus. In this kind of instances it is convenient to use the componentDidUpdate or componentDidMount methods if you want to focus the element based on a prop, or state element.
Keep in mind that as per React Lifecycle documentation, componentDidMount will only happen after rendering the component for the first time on the screen, and in this call componentDidUpdate will not occur, then for each new setState, forceUpdate call or the component receiving new props the componentDidUpdate call will occur.
componentDidMount() {
this.focusDiv();
},
componentDidUpdate() {
if(this.state.active)
this.focusDiv();
},
focusDiv() {
ReactDOM.findDOMNode(this.refs.theDiv).focus();
}
Here is a JS fiddle you can play around with.
This is the problem:
this.setState({ active: state });
this.refs.component.focus();
Set state is rerendering your component and the call is asynchronous, so you are focusing, it's just immediately rerendering after it focuses and you lose focus. Try using the setState callback
this.setState({ active: state }, () => {
this.refs.component.focus();
});
A little late to answer but the reason why your event handler is not working is probably because you are not binding your functions and so 'this' used inside the function would be undefined when you pass it as eg: "this.selectItem(color)"
In the constructor do:
this.selectItem = this.selectItem.bind(this)
this.setActive = this.setActive.bind(this)
This worked in my case
render: function(){
if(this.props.edit){
setTimeout(()=>{ this.divElement.focus() },0)
}
return <div ref={ divElement => this.divElement = divElement}
contentEditable={props.edit}/>
}