How do I use radio buttons in React?

Question

I'm making a form, and I was in need of a radio input. How do I get the checked radio input in a onSubmit-function, what is the correct way?

This is my code, I myRadioInput-variable to contain either Option A or Option B when I submit:

React.createClass({
    handleSubmit: function() {
        e.preventDefault();
        var myTextInput = this.refs.myTextInput.getDOMNode().value.trim();
        var myRadioInput = "How ?";
    },
    render: function() {
        return (
            <form onSubmit={this.handleSubmit}>
                <input type="text" ref="myTextInput" />
                <label>
                    <span>Option A</span>
                    <input type="radio" name="myRadioInput" value="Option A"/>
                </label>
                <label>
                    <span>Option B</span>
                    <input type="radio" name="myRadioInput" value="Option B"/>
                </label>
                <input type="submit" value="Submit this"/>
            </form>
        )
    }
});

Answer 1

You shouldn't use refs to get access to DOM nodes and inspect their value. Instead you should link the inputs value to a property on the component state.

Here are some examples of how to do it: https://facebook.github.io/react/docs/two-way-binding-helpers.html

Answer 2

If you make sure all your form elements have name attributes, you can extract data from the form onSubmit using form.elements:

handleSubmit: function(e) {
  e.preventDefault()
  var form = e.target
  var myTextInput = form.elements.myTextInput.value
  var myRadioInput = form.elements.myRadioInput.value
  // ...
}

In modern browsers, form.elements.myRadioInput should be a RadioNodeList which has a .value corresponding to the selected value, but when that's not supported you will get a NodeList or HTMLCollection of nodes which must be iterated over to find the selected value.

---

I also have a reusable React component - <AutoForm> - which uses a generic implementation of data extraction from form.elements for you. I've used it in the snippet below:

<meta charset="UTF-8">
<script src="http://fb.me/react-0.13.1.js"></script>
<script src="http://fb.me/JSXTransformer-0.13.1.js"></script>
<script src="https://cdn.rawgit.com/insin/react-auto-form/master/dist/react-auto-form.js"></script>
<div id="app"></div>
<script type="text/jsx;harmony=true">void function() { "use strict";
 
var Example = React.createClass({
    getInitialState() {
        return {submittedData: null}
    },

    handleSubmit(e, submittedData) {
        e.preventDefault()
        this.setState({submittedData})
    },

    render() {
        return <div>
            <AutoForm onSubmit={this.handleSubmit}>
                <input type="text" name="myTextInput" />
                <label>
                    <span>Option A</span>
                    <input type="radio" name="myRadioInput" value="Option A"/>
                </label>
                <label>
                    <span>Option B</span>
                    <input type="radio" name="myRadioInput" value="Option B"/>
                </label>
                <input type="submit" value="Submit this"/>
            </AutoForm>
            {this.state.submittedData && <pre>
              {JSON.stringify(this.state.submittedData, null, 2)}
            </pre>}
        </div>
    }
});
 
React.render(<Example/>, document.getElementById('app'))
 
}()</script>