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javascriptreactjsslidermaterial-ui

How do I identify a material-ui slider in react?


I want multiple material-ui sliders in one react component sharing a common event handler. However, to make this work, I would need to identify the originating slider. From the API documentation I can't see how that is achieved. I've tried applying id and name attributes to the <Slider>-component, yet I'm not seeing these in the synthesized event in the event handler.

handleChange = (event, value) => {
  console.log(event); // 'Id' and 'name' attributes in 'target' are empty
  this.setState({ value });
};

render() {
  const { classes } = this.props;
  const { value } = this.state;

  return (
    <div className={classes.root}>
      <Typography id="label">Slider label</Typography>
      <Slider
        classes={{ container: classes.slider }}
        value={value}
        aria-labelledby="label"
        onChange={this.handleChange}
      />
    </div>
  );
}

This is fetched from the official demo project:

https://codesandbox.io/s/4j9l9xn1o4

Any help would be greatly appreciated!


Solution

  • You can format your state like so:

    state = {
      slider1: 50, //slider1 is the name of the first slider
      slider2: 50, //slider2 is the name of the second slider
    }
    

    After that, you have 2 ways to set the state when the value of the slider is changed:

    • (Update: This method doesn't work! However I will leave it here for future reference) By using HTML attribute id, then access it by using event.target.id. The whole handleChange method would look like this:

      handleChange = (e, value) => {
        this.setState({
          [e.target.id]: value
        });
      }
      
    • By passing then name of the slider straight to the handleChange method, and it would be like this:

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

    Overall, your component should be:

    class SimpleSlider extends Component {
      state = {
        slider1: 50,
        slider2: 50
      };
    
      handleChange = name => (e, value) => {
        this.setState({
          [name]: value // --> Important bit here: This is how you set the value of sliders
        });
      };
    
      render() {
        const { classes } = this.props;
        const { slider1, slider2 } = this.state;
    
        return (
          <div className={classes.root}>
            <Typography id="label">Slider label</Typography>
            <Slider
              classes={{ container: classes.slider }}
              value={slider1}
              aria-labelledby="label"
              onChange={this.handleChange("slider1")}
            />
            <Slider
              classes={{ container: classes.slider }}
              value={slider2}
              aria-labelledby="label"
              onChange={this.handleChange("slider2")}
            />
          </div>
        );
      }
    }
    

    See it in action: https://codesandbox.io/s/4qz8o01qp4

    Edit: After running the code I found that the #1 doesn't work because the id attribute is not being passed down to the event target