Data binding in a reaction

Question

Hi, I am new to reacting and it is hard for me to understand how data binding in responsejs works. I did data binding in AngularJS, but in reactions it seems more complicated.

What I want to do is when I enter text in the input field, it should appear elsewhere in real time.

This is my input

<div className="post_input">

    <input className='post_data_input_overlay' placeholder="Ask your question here" ref="postTxt"/>

</div>

So, when I enter something into this input field, it should appear somewhere else. How can i do this?

Answer 1

Binding data in a reagent can be achieved using controlled input. A controlled input is achieved by binding the value to the event state variableand a onChangeto change the state when the input value changes.

See snippet below.

class App extends React.Component {
  constructor() {
    super();
    this.state = {value : ''}
  }
  handleChange = (e) =>{ 
    this.setState({value: e.target.value});
  }
  render() {
    return (
    <div>
        <input type="text" value={this.state.value} onChange={this.handleChange}/>
        <div>{this.state.value}</div>
    </div>
   )
  }
}
ReactDOM.render(<App/>, document.getElementById('app'));

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.js"></script>
<div id="app"></div>

Run codeHide result

Answer 2

, React .

, , state : , :

class NameForm extends React.Component {
  constructor(props) {
    super(props);
    this.state = {value: ''};

    this.handleChange = this.handleChange.bind(this);
  }

  handleChange(event) {
    this.setState({value: event.target.value});
  }

  render() {
    return (
      <input type="text" value={this.state.value} onChange={this.handleChange} />
    );
  }
}

https://facebook.imtqy.com/react/docs/forms.html

, , React . , React, :

var WithLink = React.createClass({
  mixins: [LinkedStateMixin],
  getInitialState: function() {
    return {message: 'Hello!'};
  },
  render: function() {
    return <input type="text" valueLink={this.linkState('message')} />;
  }
});

https://facebook.imtqy.com/react/docs/two-way-binding-helpers.html

refs, , DOM , . https://facebook.imtqy.com/react/docs/refs-and-the-dom.html.

Answer 3

, , .

, , ES6 , :

class LovelyForm extends React.Component {
  constructor(props) {
  alert("Construct");
    super(props);
    this.state = {
      field1: "Default 1",
      field2: "Default 2"
    };
  }

  update = (name, e) => {
    this.setState({ [name]: e.target.value });
  }

  render() {
    return (
      <form>
        <p><input type="text" value={this.state.field1} onChange={(e) => this.update("field1", e)} />
          {this.state.field1}</p>
        <p><input type="text" value={this.state.field2} onChange={(e) => this.update("field2", e)} />
          {this.state.field2}</p>
      </form>
    );
  }
}
ReactDOM.render(<LovelyForm/>, document.getElementById('example'));

<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 id="example"></div>

Hide result

Answer 4

React ( ) , , . :

const MyComponent = () => {
    const [value, setValue] = React.useState('some initial value');
    return <input value={value} onChange={e => setValue(e.target.value)} />;
}

, . , , . .

. , . , , , , Hookstate ( : ). .

, : ( ) . Hookstate. 5000 : , .

Answer 5

, , React .

, , . , React . React . .

import { LinkedComponent } from 'valuelink'

class Test extends LinkedComponent {
    state = { a : "Hi there! I'm databinding demo!" };

    render(){
        // Bind all state members...
        const { a } = this.linkAll();

        // Then, go ahead. As easy as that.
        return (
             <input type="text" ...a.props />
        )
    }
}

, - React. 5- ,

Answer 6

class App extends React.Component {
  constructor() {
    super();
    this.state = {value : ''}
  }
  handleChange = (e) =>{ 
    this.setState({value: e.target.value});
  }
  render() {
    return (
    <div>
        <input type="text" value={this.state.value} onChange={this.handleChange}/>
        <div>{this.state.value}</div>
    </div>
   )
  }
}
ReactDOM.render(<App/>, document.getElementById('app'));

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.js"></script>
<div id="app"></div>

Hide result

Answer 7

, :

-

class SomeComponent extends React.Component {
  state = {
    first_name: "George"
  };

  render() {
    return (
      <Form binding={this}>
        <Input name="first_name" />
      </Form>
    );
  }
}

https://www.npmjs.com/package/react-distributed-forms#data-binding

React,

Answer 8

setState() Reaction.js

React-

, angularjs

setState

.

import React, { Component } from 'react';
import { render } from 'react-dom';
import Rcp from 'react-chopper';

class App extends Component {
  constructor(props) {
    super(props);
    this.state = {
      name: 'React'
    };
    this.modal = Rcp(this.state, this);
  }

  tank = () => {
    console.log(this.modal)
  }
  render() {
    return (
      <div>
        <input value={this.modal.name} onChange={e => this.modal.name = e.target.value} />
        <p> Bang Bang {this.modal.name} </p>
        <button onClick={() => this.tank()}>console</button>
      </div>
    );
  }
}

render(<App />, document.getElementById('root'));

, Pr ...

Answer 9

Hooks React, .

import React, { useState, useEffect } from 'react'
import ReactDOM from 'react-dom';

const Demo = props =>{
    const [text, setText] = useState("there");
    return props.logic(text, setText);
};

const App = () => {
    const [text, setText] = useState("hello");

    const componentDidMount = () =>{
        setText("hey");
    };
    useEffect(componentDidMount, []);

    const logic = (word, setWord) => (
        <div>
            <h1>{word}</h1>
            <input type="text" value={word} onChange={e => setWord(e.target.value)}></input>
            <h1>{text}</h1>
            <input type="text" value={text} onChange={e => setText(e.target.value)}></input>
        </div>
    );
    return <Demo logic={logic} />;
};

ReactDOM.render(<App />,document.getElementById("root"));

Answer 10

Define state attributes. Add a universal handleChange event handler. Add the parameter name to the input tag to map.

this.state = { stateAttrName:"" }

handleChange=(event)=>{
    this.setState({[event.target.name]:event.target.value });
  } 

<input className="form-control" name="stateAttrName" value= 
{this.state.stateAttrName} onChange={this.handleChange}/>