How to add and remove table rows Dynamically in React.js

Question

 my attempt fiddle here ..........

https://jsfiddle.net/techboy0007/j1eas924/

https://i.sstatic.net/KXFot.png

Answer 1

You can achieve that by playing with react state. In your case you are using nested objects so you need to be carefully when you update them.

It's not a good idea to mutate your state because it can cause easily bugs or an unexpected behavior.

Look closely how the handling functions are working.

Here you have a live demo.

class App extends React.Component {
  state = {
    rows: []
  };
  handleChange = idx => e => {
    const { name, value } = e.target;
    const rows = [...this.state.rows];
    rows[idx] = {
      [name]: value
    };
    this.setState({
      rows
    });
  };
  handleAddRow = () => {
    const item = {
      name: "",
      mobile: ""
    };
    this.setState({
      rows: [...this.state.rows, item]
    });
  };
  handleRemoveRow = () => {
    this.setState({
      rows: this.state.rows.slice(0, -1)
    });
  };
  render() {
    return (
      <div>
        <div className="container">
          <div className="row clearfix">
            <div className="col-md-12 column">
              <table
                className="table table-bordered table-hover"
                id="tab_logic"
              >
                <thead>
                  <tr>
                    <th className="text-center"> # </th>
                    <th className="text-center"> Name </th>
                    <th className="text-center"> Mobile </th>
                  </tr>
                </thead>
                <tbody>
                  {this.state.rows.map((item, idx) => (
                    <tr id="addr0" key={idx}>
                      <td>{idx}</td>
                      <td>
                        <input
                          type="text"
                          name="name"
                          value={this.state.rows[idx].name}
                          onChange={this.handleChange(idx)}
                          className="form-control"
                        />
                      </td>
                      <td>
                        <input
                          type="text"
                          name="mobile"
                          value={this.state.rows[idx].mobile}
                          onChange={this.handleChange(idx)}
                          className="form-control"
                        />
                      </td>
                    </tr>
                  ))}
                </tbody>
              </table>
              <button
                onClick={this.handleAddRow}
                className="btn btn-default pull-left"
              >
                Add Row
              </button>
              <button
                onClick={this.handleRemoveRow}
                className="pull-right btn btn-default"
              >
                Delete Row
              </button>
            </div>
          </div>
        </div>
      </div>
    );
  }
}

render(<App />, document.getElementById("root"));

PD: If I can give you a recommendation I'd say that you need to study a little bit more about react - javascript to move forward, it would help to achieve things like this faster, right now you probably need to focus on understand the basics.

Answer 2

Incase someone might be looking for a React hooks version, this is a sample implementation of Arnold's answer:

import React, { useState } from "react";

const App = () => {
  const [rows, setRows] = useState([{}]);
  const collumnsArray = ["name", "id", "mobile", "date", "amount"]; // pass collumns here dynamically

  const handleAddRow = () => {
    const item = {};
    setRows([...rows, item]);
  };

  const postResults = () => {
    console.log(rows); // there you go, do as you please
  };
  const handleRemoveSpecificRow = (idx) => {
    const tempRows = [...rows]; // to avoid  direct state mutation
    tempRows.splice(idx, 1);
    setRows(tempRows);
  };

  const updateState = (e) => {
    let prope = e.target.attributes.collumn.value; // the custom collumn attribute
    let index = e.target.attributes.index.value; // index of state array -rows
    let fieldValue = e.target.value; // value

    const tempRows = [...rows]; // avoid direct state mutation
    const tempObj = rows[index]; // copy state object at index to a temporary object
    tempObj[prope] = fieldValue; // modify temporary object

    // return object to rows` clone
    tempRows[index] = tempObj;
    setRows(tempRows); // update state
  };

  return (
    <div>
      <div className="container">
        <div className="row clearfix">
          <div className="col-md-12 column">
            <table className="table table-bordered table-hover" id="tab_logic">
              <thead>
                <tr>
                  <th className="text-center"> # </th>
                  {collumnsArray.map((collumn, index) => (
                    <th className="text-center" key={index}>
                      {collumn}
                    </th>
                  ))}
                  <th />
                </tr>
              </thead>
              <tbody>
                {rows.map((item, idx) => (
                  <tr key={idx}>
                    <td>{idx + 1}</td>
                    {collumnsArray.map((collumn, index) => (
                      <td key={index}>
                        <input
                          type="text"
                          collumn={collumn}
                          value={rows[idx][collumn]}
                          index={idx}
                          className="form-control"
                          onChange={(e) => updateState(e)}                             
                          
                        />
                      </td>
                    ))}

                    <td>
                      <button
                        className="btn btn-outline-danger btn-sm"
                        onClick={() => handleRemoveSpecificRow(idx)}
                      >
                        Remove
                      </button>
                    </td>
                  </tr>
                ))}
              </tbody>
            </table>
            <button onClick={handleAddRow} className="btn btn-primary">
              Add Row
            </button>
            <button
              onClick={postResults}
              className="btn btn-success float-right"
            >
              Save Results
            </button>
          </div>
        </div>
      </div>
    </div>
  );
};

export default App;

Answer 3

Thanks for the answer above. Just a little bit comment on handling of 'handleChange'. Do we need to change the following

    rows[idx] = {
      [name]: value
    };

to the following for saving the data into rows:

const rowInfo = rows[idx];
rowInfo[name] = value;

Answer 4

If you want to add/remove rows dynamically you can play with the state, or if you where using Redux you can play with the store.

Here's a simple example using a components local state to add and remove rows:

https://codesandbox.io/s/k302jwn44r

EDIT: fixed mutating state

import React from "react";
import { render } from "react-dom";

const styles = {
  fontFamily: "sans-serif",
  textAlign: "left"
};

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

  handleAddRow = () => {
    this.setState((prevState, props) => {
      const row = {content: "hello this is a new row!" };
      return { rows: [...prevState.rows, row] };
    });
  };

  handleRemoveRow = () => {
    this.setState((prevState, props) => {
      return { rows: prevState.rows.slice(1) };
    });
  };

  render() {
    console.log(this.state);
    return (
      <div style={styles}>
        <table>
          <tbody>
            {this.state.rows.map(row => (
              <tr>
                <td>{row.content}</td>
              </tr>
            ))}
            <tr>
              <td className="" onClick={this.handleAddRow}>
                (+)
              </td>
              {Boolean(this.state.rows.length) && (
                <td onClick={this.handleRemoveRow}>(-)</td>
              )}
            </tr>
          </tbody>
        </table>
      </div>
    );
  }
}

render(<App />, document.getElementById("root"));