React: binding an array to dynamically added fields

Question

Let's say I have a class with an array of state level

ElementsClass = React.createClass({
    getInitialState: function() {
      return {
          elements: []
      }
    },
    addElement: function() {
        var element = {
            name: ""
        };
    },
    render() {
        return (
            {this.state.elements.map(function (element, i) {
                    return <input value={element.name} />
                }
            )}
        )
}

The idea is that I can dynamically add elements to the array and a new input field appears.

How can I bind the data so that I can change the value in the input field and that they are automatically reflected in the correct element in the array of elements?

Answer 1

To dynamically synchronize your inputs with your state array, you can use someting with the name linkStatefrom the react-catalyst package . Once you have installed it using npm, you can use it as follows:

 //need to import
import Catalyst from 'react-catalyst'; 

ElementsClass = React.createClass({
    // mixin the linkedstate component
    mixins : [Catalyst.LinkedStateMixin],       

    getInitialState: function() {
      return {
          elements: []
      }
    },
    addElement: function() {
        var element = {
            name: ""
        };

        //add to elements array
        this.state.elements.push(element);

        //let react know to rerender necessary parts
        this.setState({
            elements : this.state.elements
        });
    },
    render() {
        return (
            {this.state.elements.map(function (element, i) {
                    //use the linkState method
                    return <input valueLink={this.linkState('elements.'+i+'.name')} />
                }
            )}
        )
}

, react-catalyst, , React valueLink , elements. , , , , .

: , , . - ( ):

{this.state.elements.map(function (element, i) {
        //use the linkState method
        return <input valueLink={this.linkState('elements.'+i+'.name')} key={'elinput' + i} />
    }
)}

, .

Answer 2

ES5 React, :

var ElementsClass = React.createClass({

getInitialState: function() {
  return {
      elements: []
  }
},
createElement: function(){
  var element = {
    name: ''
  };
  this.setState({elements: this.state.elements.concat(element)});
},
updateElement: function(pos, event) {
    var value = event.target.value;
    var updatedElements = this.state.elements.map(function(element, i){
      if (i === pos){
        return {name: value};
      }
      return element;
    });
    this.setState({elements: updatedElements});
},
render: function() {
    console.log(this.state.elements);
    return (
      <div>
        {this.state.elements.map(function (element, i) {
           var boundClick = this.updateElement.bind(this, i);
           return <input key={i} onKeyUp={boundClick}/>
        }.bind(this))}
        <button onClick={this.createElement}>Add Element</button>
      </div>
    )
}
});

React.render(<ElementsClass />, document.getElementById('app'));

, , push on.

Answer 3

.

State and Forms in Action, Part 3: Handling a Complex State

import Link from 'valuelink';

// linked inputs will be deprecated, thus we need to use custom wrappers 
import { Input } from 'valueLink/tags.jsx'

const ElementsClass = React.createClass({
    getInitialState: function() {
      return {
          elements: []
      }
    },

    render() {
        // Take link to the element
        const elementsLink = Link.state( this, 'elements' );

        return (
            <div>
                { elementsLink.map( ( elementLink, i ) => (
                     <Input key={ i } valueLink={ elementLink.at( 'name' ) } />  
                ))}

                <button onClick={ elementsLink.push({ name : '' })}>
                    Add Elements
                </button>
            </div>
        );
    }
});