reactjs how to handle value change on input array properly

Question

I have this form invoice registration created in reactJs.

The Form should handle input array (marked with red outline). whenever onChange event occured on the input. all the input is receiving the same value. How to prooperly handle this ? I intended to use this input value to generated data like this below :

[
    {
        invoice_number:102947303364,
        invoice_registration_no : 1235
    },
    {
        invoice_number:102947109177,
        invoice_registration_no : 6578
    },
]

Thanks in advance for the help.

Its look like you are binding the referance and not value

RIYAJ KHAN
– RIYAJ KHAN

2017-08-10 04:58:43 +00:00
Commented Aug 10, 2017 at 4:58 — RIYAJ KHAN
– RIYAJ KHAN, Commented Aug 10, 2017 at 4:58

HyeonJunOh · Accepted Answer · 2017-08-10 04:41:10Z

5

I do not know which is the primary key in DB, so I assumed invoice_number is the primary key.

class CustomList extends React.Component {
  constructor(props){
    super(props);
    this.handleInputChange = this.handleInputChange.bind(this);
    this.renderList = this.renderList.bind(this);
    
    this.state = {
      data: [
          {
              invoice_number:102947303364,
              invoice_registration_no : 1235,
              some_value: '',
          }, {
              invoice_number:102947109177,
              invoice_registration_no : 6578,
              some_value: '',
          },
      ],
    }
  }
  
  handleInputChange(e){
    const {id, value} = e.target;
    let {data} = this.state;
    const targetIndex = data.findIndex(datum => {
      return datum.invoice_number == id;
    });

    if(targetIndex !== -1){
      data[targetIndex].some_value = value;
      this.setState({data});
    }
  }
  
  renderList() {
      const {data} = this.state;
      let content = data.map(datum => {
        return (
          <li id={datum.invoice_number}>
            <p>{datum.invoice_number}</p>
            <input type="text" id={datum.invoice_number} value={datum.some_value}
              onChange={this.handleInputChange}/>
          </li>
        )
      });
      return (
        <ul>
          {content}
        </ul>
      )
  }
  
  render() {
    const myList = this.renderList();
    return (
      <div>
        {myList}
      </div>
    );
  }
}
ReactDOM.render(
  <CustomList/>,
  document.getElementById('root')
)

<html>
  <body>
    <div id="root"></div>
  </body>
</html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>

what you need to see is handleInputChange method binds to CustomList class and renderList.

I just set id property to invoice_number at each input and find changed input's index using Array.prototype.findIndex.

answered Aug 10, 2017 at 4:41

HyeonJunOh

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5 Comments

Nocebo Over a year ago

You could also declare handleInputChange like this: handleInputChange = () => {...}. Then you don't need to bind them in this ugly fashion :D

HyeonJunOh Over a year ago

@Nocebo In fact, I usually use ::this.method which is ES6 grammer to bind method to class. However Stack Overflow doesn't support ES6, so I habitually wrote like this. Thank you for telling me!

Nocebo Over a year ago

Oh I see. Yeah just trying to help ;) Have a nice day :)

HyeonJunOh Over a year ago

@Nocebo Thank you again for your advice :)

coderX Over a year ago

@HyeonJunOh Thanks. Can you please tell how to highlight particular input box border and render small error text when certain required input are left empty when user clicks on Submit button ? I know how to do it for few input element on screen but how to do it for array of objects.

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