如何使用 lodash 用 1 个油门来控制多个按钮？

Question

I'd like to avoid concurrence and restrict the action by 1 per second.

This is because the onChange event also trigger a slide show of 1s duration, and triggering twice is corrupting the UI.

I initially started with 4 debounces function, but finally got to this:

import React from 'react';
import { css } from 'styled-components';
import PropTypes from 'prop-types';
import omit from 'lodash.omit';
import throttle from 'lodash.throttle';
import Img from '@bootstrap-styled/v4/lib/Img';

export default class ServicesAndSolutionImg extends React.PureComponent {
  static propTypes = {
    src: PropTypes.string.isRequired,
    alt: PropTypes.string.isRequired,
    onDigitalSolution: PropTypes.func.isRequired,
    onServices: PropTypes.func.isRequired,
    onHosting: PropTypes.func.isRequired,
    onAddons: PropTypes.func.isRequired,
  };

  state = {
    throttleFn: null,
  }

  componentWillMount() {
    this.setState({
      throttleFn: (e) => throttle(this.props[e.target.value], 1000, { leading: false, trailing: true })(),
    });
  }

  render() {
    const { src, alt } = omit(this.props, [
      'onDigitalSolution',
      'onServices',
      'onHosting',
      'onAddons',
    ]);

    return (
      <div css={css`position: relative`}>
        <Img fluid src={src} alt={alt} className="w-100 pt-3 pl-5 pr-5" />
        <div css={css`
          position: absolute;
          top: 0;
          right: 0;
          left: 0;
          right: 0;
          width: 100%;
          height: 100%;
        `}>
          <div css={css`
            position: relative;
            width: inherit;
            height: inherit;
            button {
              cursor: pointer;
              position: absolute;
              top: 23%;
              height: 51%;
              opacity: 0;
            }
            button:nth-child(1) {
              left: 15%;
              width: 16%;
            }
            button:nth-child(2) {
              left: 32%;
              width: 16%;
            }
            button:nth-child(3) {
              left: 48%;
              width: 16%;
            }
            button:nth-child(4) {
              left: 65%;
              width: 16%;
            }
          `}>
            <button onClick={this.state.throttleFn} value="onDigitalSolution" />
            <button onClick={this.state.throttleFn} value="onServices" />
            <button onClick={this.state.throttleFn} value="onHosting" />
            <button onClick={this.state.throttleFn} value="onAddons" />
          </div>
        </div>
      </div>
    );
  }
}

Expected

No delay, 1 click per second, no concurrency

Result

1 second delay, up to 4 concurrent actions.

Does anybody know why this fails?

Answer 1

Throttle is a function that takes a function, and returns a throttled function. The throttled function only invokes the original function once in a window of x milliseconds.

Calling throttle multiple times, returns multiple throttled functions, which you invoke, and each of them is the only call in the window of time.

To fix that, assign the result of calling throttle on the callback to a property on the component, and call that function when you register the click events.

export default class ServicesAndSolutionImg extends React.PureComponent {
  static propTypes = {
    src: PropTypes.string.isRequired,
    alt: PropTypes.string.isRequired,
    onDigitalSolution: PropTypes.func.isRequired,
    onServices: PropTypes.func.isRequired,
    onHosting: PropTypes.func.isRequired,
    onAddons: PropTypes.func.isRequired,
  };

  // create the throttled function
  throttleFn = throttle((e) => this.props[e.target.value], 1000, { leading: false, trailing: true })

  render() {
     // no need to omit anything - you know what you want
    const { src, alt } = this.props;

    return (
      <div css={css`position: relative`}>
        <Img fluid src={src} alt={alt} className="w-100 pt-3 pl-5 pr-5" />
        <div css={css`
          position: absolute;
          top: 0;
          right: 0;
          left: 0;
          right: 0;
          width: 100%;
          height: 100%;
        `}>
          <div css={css`
            position: relative;
            width: inherit;
            height: inherit;
            button {
              cursor: pointer;
              position: absolute;
              top: 23%;
              height: 51%;
              opacity: 0;
            }
            button:nth-child(1) {
              left: 15%;
              width: 16%;
            }
            button:nth-child(2) {
              left: 32%;
              width: 16%;
            }
            button:nth-child(3) {
              left: 48%;
              width: 16%;
            }
            button:nth-child(4) {
              left: 65%;
              width: 16%;
            }
          `}>
            <button onClick={this.throttleFn} value="onDigitalSolution" />
            <button onClick={this.throttleFn} value="onServices" />
            <button onClick={this.throttleFn} value="onHosting" />
            <button onClick={this.throttleFn} value="onAddons" />
          </div>
        </div>
      </div>
    );
  }
}