CODEWITHSUNDEEP
javascriptreactjslodash
ellerymoon
ellerymoon

Reputation: 35

how to pass parameters inside of 'lodash' function(debounce) callback function?

I've been making a component (react.js) that has two events : onClick event and onDoubleClick event.

According to the W3C's DOM spec, it's impossible to distinguish single-click events from click events that lead to a dblclick event.

So I've been making a single event that has a conditional statement.

Here is my inner class component's function code.

    handleClick = (e) => {
     if(!this._delayedClick) {
      this._delayedClick = _.debounce(this.onChangeTargetLabel, 200)
     }
     if(this.clickedOnce) {
      this._delayedClick.cancel()
      this.clickedOnce = false
      this.editLabel()
      console.log('doubleClick')
     } else {
      this._delayedClick(e)
      this.clickedOnce = true
      console.log('Click')
     }
    }

   onChangeTargetLabel = (e) => { // click label event
    console.log(e)
    this.clickedOnce = undefined
    const { label } = this.props
    label.onChangeTargetLabel(e.target.value)
   }

    editLabel = () => { // doubleClick label event
     const { label } = this.props
     label.editLabel()
   }

This code's problems is that once handleClick functions is executed, after 200ms , the debounce callback function is executed , and callback function(this.onChangeTargetLabel) doesn't have any parameters.

I want to bind handleClicks parameter and this.onChangeTargetlabel's parameters.

How can i do that? Thanks.

Upvotes: 2

Views: 2572

Answers (1)

Tholle
Tholle

Reputation: 112787

It's not a good idea to use the event asynchronously, so you could take out the value in the handleClick function and give that to onChangeTargetLabel instead.

handleClick = e => {
  if (!this._delayedClick) {
    const { value } = event.target;
    this._delayedClick = _.debounce(this.onChangeTargetLabel.bind(this, value), 200);
  }

  // ...
};

onChangeTargetLabel = value => {
  this.clickedOnce = undefined;
  label.onChangeTargetLabel(value);
};

You could also use a setTimeout instead of a debounced function if you prefer:

class App extends React.Component {
  timeout = null;

  onClick = event => {
    if (this.timeout) {
      console.log("Double click!");
      clearTimeout(this.timeout);
      this.timeout = null;
    } else {
      console.log("click");
      this.timeout = setTimeout(() => {
        this.timeout = null;
      }, 200);
    }
  };

  render() {
    return <button onClick={this.onClick}>Click me</button>;
  }
}

Upvotes: 2

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