How to pass parameter in a function on onClick event

Question

I am trying to make a component which receiving a function as a props. i want to pass some value into function while calling it:

class Course extends Component {
    render() {
        return (
             <div>
                 <div id="courses">
                      <p onClick={this.props.sumPrice}>{this.props.name}<b>{this.props.price}</b></p>
                 </div>
             </div>
        );
     }
 }

sumPrice is a function define in parent component and its need a value. This is my sumPrice function and parent class constructor code:

constructor(props) {
    super(props);

    this.state = {
        active: false,
        total: 0
    };

    this.sumPrice = this.sumPrice.bind(this);
}

sumPrice(price) {
    this.setState({ total: this.state.total + price });
}

Xarvalus · Accepted Answer · 2019-05-11 14:25:34Z

4

Usually the closure, arrow function in render handles such situations exactly how it is needed:

<div id="courses">
    <p
      onClick={() => this.props.sumPrice(this.props.price)}
    >
      { this.props.name }<b>{ this.props.price }</b>
    </p>
</div>

While it works as expected, unfortunately it comes at cost ot performance penalty Why shouldn't JSX props use arrow functions or bind?. The impact does not have to be dramatic problem but should be generally avoided.

The optimal solution is to use the functions which are not recreated on each re-render, like class method:

class Course extends Component {
    constructor(props) {
        super(props)

        this.onClick = this.onClick.bind(this)
    }

    onClick () {
      const { sumPrice, price } = this.props

      sumPrice(price)
    }

    render() {
        return (
             <div>
                 <div id="courses">
                      <p onClick={this.onClick}>{this.props.name}<b>{this.props.price}</b></p>
                 </div>
             </div>
        )
     }
  }

Avoiding performance issues.

edited May 11, 2019 at 14:25

answered Jun 21, 2018 at 23:47

Xarvalus

3,0312 gold badges23 silver badges30 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

vivek modi Over a year ago

this solution is giving Cannot read property 'props' of undefined error

Xarvalus Over a year ago

The second solution also needs manually binding eg in constructor like it was in this.sumPrice.bind(this). this.onClick = this.onClick.bind(this)

Collectives™ on Stack Overflow

How to pass parameter in a function on onClick event

1 Answer 1

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related