I'm building an app where I want the user to specify a number of text fields and then render this amount of fields dynamically. I'm having trouble setting up the state so that it is unique for each field. Here is the code segment:

        var fieldsArray = [];

        for(var i = 0; i <= this.props.numToShow; i ++){
        fieldsArray.push(
            <div>
                <label>
                    <div className="label">{i}</div> 
                    <input type='text' value={this.state.value} name={this.state.value} onChange={this.handleChange} />
                </label>
            </div>
            );
        }

    return (
      <div className = 'inputs'>
        {fieldsArray}
      </div>
    );

Currently, when I change one of the fields, all the other fields update with that unique fields state. Here is the handleChange function that sets the state:

    handleChange: function(e){
       this.setState({
           value: e.target.value,
       });
    }

Is it possible to initialize the state as an array and keep track of the inputs that way? Or is there a better way to do this?

I'm building an app where I want the user to specify a number of text fields and then render this amount of fields dynamically. I'm having trouble setting up the state so that it is unique for each field. Here is the code segment:

        var fieldsArray = [];

        for(var i = 0; i <= this.props.numToShow; i ++){
        fieldsArray.push(
            <div>
                <label>
                    <div className="label">{i}</div> 
                    <input type='text' value={this.state.value} name={this.state.value} onChange={this.handleChange} />
                </label>
            </div>
            );
        }

    return (
      <div className = 'inputs'>
        {fieldsArray}
      </div>
    );

Currently, when I change one of the fields, all the other fields update with that unique fields state. Here is the handleChange function that sets the state:

    handleChange: function(e){
       this.setState({
           value: e.target.value,
       });
    }

Is it possible to initialize the state as an array and keep track of the inputs that way? Or is there a better way to do this?

• javascript
• reactjs

2 Answers 2

Keeping an array of values in state would work fine. You'll just have to make sure you're passing the index of the input so you know what to update. bind helps with this:

class YourComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = { values: [] };
  }

  handleChange(i, e) {
    this.setState({
      values: { ...this.state.values, [i]: e.target.value }
    });
  }

  render() {
    var fieldsArray = [];

    for (var i = 0; i <= this.props.numToShow; i++) {
      fieldsArray.push(
        <div>
            <label>
                <div className="label">{i}</div> 
                <input 
                  type='text' 
                  value={this.state.values[i]} 
                  name={this.state.values[i]} 
                  onChange={this.handleChange.bind(this, i)} />
            </label>
        </div>
      );
    }

    return (
      <div className = 'inputs'>
        {fieldsArray}
      </div>
    );
  }
}

                               onChange={(e) => {
                                    var newPresetList = [...presetList]

                                    newPresetList.map((_item) => {
                                      if (_item.id === item.id) {
                                        _item.preset_name = e.target.value
                                        return
                                      }
                                    })
                                    setPresetList(newPresetList)
                                  }}