React editable table

Question

I have built a React table like so:

const Table = ({data}) => {

    return (
        <table className="table table-bordered">
            <thead>
                <tr>
                    <th>Qty</th>
                    <th>Description</th>
                    <th>Price (£)</th>
                </tr>
            </thead>
            <tbody>
                {data.map((row) => {
                    return (
                        <tr>
                            <td><input type='number' className='form-control' step='1' min="1" value={row[0]}/></td>
                            <td><input type='text' className='form-control' value={row[1]}/></td>
                            <td><input type='text' className='form-control' placeholder='6.00' value={row[2]}/></td>
                        </tr>
                    );
                })}
            </tbody>
        </table>
    );
};

Table.propTypes = {
    data: React.PropTypes.array.isRequired
};

export default Table;

In the class I am using this component I am passing data as a parameter (which is initially empty):

materials: [[],[],[],[],[],[],[],[],[],[]] //Initialise with 10 empty rows 


<Table data={materials} />

This will build up a table with 10 empty rows. The only problem now is that when I enter data into the table, the data array that I have mapped does not update with the data I have entered.

I think what I need is some event where I can update the data with a snapshot of what has been entered but I am not sure how to implement this. Any help would be greatly appreciated.

Answer 1

React doesn't work with two-way data binding, like Angular JS does, for instance. props are read-only, so you would need update them where they belong.

For instance, the parente component, where <Table /> is declared could have materials array in its state and, besides passing materials as props, it could pass a function handler like onCellChange(row, column), so you could bind it with the onChange events in the inputs elements.

Like so,

const Table = ({data, onCellChange}) => {

 return (
    <table className="table table-bordered">
        <thead>
            <tr>
                <th>Qty</th>
                <th>Description</th>
                <th>Price (£)</th>
            </tr>
        </thead>
        <tbody>
            {data.map((row, index) => {
                return (
                    <tr key={index}>
                        <td><input type='number' className='form-control' step='1' min="1" value={row[0]} onChange={() => onCellChange(index, 0)}/></td>
                        <td><input type='text' className='form-control' value={row[1]} onChange={() => onCellChange(index, 1)}/></td>
                        <td><input type='text' className='form-control' placeholder='6.00' value={row[2]}  onChange={() => onCellChange(index, 2)}/></td>
                    </tr>
                );
            })}
        </tbody>
    </table>
  );
};

Table.propTypes = {
    data: React.PropTypes.array.isRequired
};

So, at the parent component, you would declare the component like <Table data={this.state.materials} onCellChange={this.onCellChange} />.

And it would have a method like this:

onCellChange: function(row, column) {
    //update the cell with this.setState() method
}

Answer 2

You can achieve this by maintaining state of your table data. I've made a rough structure of how you could do it here: http://codepen.io/PiotrBerebecki/pen/QKrqPO

Have a look at the console output which shows state updates.

class Table extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      materials: props.data
    };
  }

  handleChange(index, dataType, value) {
    const newState = this.state.materials.map((item, i) => {
      if (i == index) {
        return {...item, [dataType]: value};
      }
      return item;
    });

    this.setState({
       materials: newState
    });
  }

  render() {
    console.clear();
    console.log(JSON.stringify(this.state.materials));
    return (
        <table className="table table-bordered">
            <thead>
                <tr>
                    <th>Qty</th>
                    <th>Description</th>
                    <th>Price (£)</th>
                </tr>
            </thead>
            <tbody>
                {this.state.materials.map((row, index) => {
                    return (
                        <tr>
                            <td>
                              <input onChange={(e) => this.handleChange(index, 'qty', e.target.value)} 
                                     type='number' 
                                     className='form-control' 
                                     step='1' min="1"
                                     value={this.state.materials[index].qty}/>
                            </td>
                            <td>
                              <input onChange={(e) => this.handleChange(index, 'desc', e.target.value)} 
                                     type='text' 
                                     className='form-control'
                                     value={this.state.materials[index].desc}/>
                            </td>
                            <td>
                              <input onChange={(e) => this.handleChange(index, 'price', e.target.value)} 
                                     type='text'
                                     className='form-control'  
                                     placeholder='6.00'
                                     value={this.state.materials[index].price}/>
                            </td>
                        </tr>
                    );
                })}
            </tbody>
        </table>
    );
  }
}


const materials = [
  { qty: '', desc: '', price: '' },
  { qty: '', desc: '', price: '' },
  { qty: '', desc: '', price: '' },
  { qty: '', desc: '', price: '' },
  { qty: '', desc: '', price: '' },
  { qty: '', desc: '', price: '' },
  { qty: '', desc: '', price: '' },
  { qty: '', desc: '', price: '' }
]


ReactDOM.render(<Table data={materials} />, document.getElementById('app'));

Answer 3

you need to update the state onChange:

  getInitialState: function() {
    return {value: 'Hello!'};
  },
  handleChange: function(event) {
    this.setState({value: event.target.value});
  },
  render: function() {
    return (
      <input
        type="text"
        value={this.state.value}
        onChange={this.handleChange}
      />
    );
  }