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React Checkbox not sending onChange

Posted by: admin November 30, 2017 Leave a comment

Questions:

TLDR: Use defaultChecked instead of checked, working jsbin here http://jsbin.com/mecimayawe/1/edit?js,output

Trying to setup a simple checkbox that will cross out its label text when it is checked. For some reason handleChange is not getting fired when I use the component. Can anyone explain what I’m doing wrong?

var CrossoutCheckbox = React.createClass({
  getInitialState: function () {
    return {
        complete: (!!this.props.complete) || false
      };
  },
  handleChange: function(){
    console.log('handleChange', this.refs.complete.checked); // Never gets logged
    this.setState({
      complete: this.refs.complete.checked
    });
  },
  render: function(){
    var labelStyle={
      'text-decoration': this.state.complete?'line-through':''
    };
    return (
      <span>
        <label style={labelStyle}>
          <input
            type="checkbox"
            checked={this.state.complete}
            ref="complete"
            onChange={this.handleChange}
          />
          {this.props.text}
        </label>
      </span>
    );
  }
});

Usage:

React.renderComponent(CrossoutCheckbox({text: "Text Text", complete: false}), mountNode);

Solution:

Using checked doesn’t let the underlying value change (apparently) and thus doesn’t call the onChange handler. Switching to defaultChecked seems to fix this:

var CrossoutCheckbox = React.createClass({
  getInitialState: function () {
    return {
        complete: (!!this.props.complete) || false
      };
  },
  handleChange: function(){
    this.setState({
      complete: !this.state.complete
    });
  },
  render: function(){
    var labelStyle={
      'text-decoration': this.state.complete?'line-through':''
    };
    return (
      <span>
        <label style={labelStyle}>
          <input
            type="checkbox"
            defaultChecked={this.state.complete}
            ref="complete"
            onChange={this.handleChange}
          />
          {this.props.text}
        </label>
      </span>
    );
  }
});
Answers:

To get the checked state of your checkbox the path would be:

this.refs.complete.state.checked

The alternative is to get it from the event passed into the handleChange method:

event.target.checked

Questions:
Answers:

In material ui, state of checkbox can be fetched as

this.refs.complete.state.switched