反应：onKeyDown 事件的去抖动

Question

我在我的 React 类组件中有输入：

changeVal(event) {
  console.log(event.keyKode)
}
...

return(
   <input onKeyDown={event => this.changeVal(event)} />
)

如何在没有 lodash 的情况下以 500 毫秒的去抖动在 keyDown 上调用函数？

我尝试了下一件事：

debounce = (callback, delay) => {
    const timerClear = () => clear = true;
    var clear = true;
    return event => {
        if (clear) { 
            clear = false;
            setTimeout(timerClear, delay);
            callback(event);
        }
    }
}

return(
   <input onKeyDown={event => this.debounce(this.changeVal, 500)} />
)

但这根本行不通。

Answer 1

debounce 函数的返回值应直接用作处理程序。在此处查看示例：https://codesandbox.io/s/musing-dust-iy7tq

class App extends React.Component {
  changeVal(event) {
    console.log(event.keyCode)
  }

  debounce = (callback, delay) => {
    const timerClear = () => clear = true;
    var clear = true;
    return event => {
        if (clear) { 
            clear = false;
            setTimeout(timerClear, delay);
            callback(event);
        }
    }
}

  render() {
    return(
       <input onKeyDown={this.debounce(this.changeVal, 1500)} />
    )
  }
}

Answer 2

试试

const debounce = (func, wait = 500) => {
  let timeout;
  return function(...args) {
    clearTimeout(timeout);
    timeout = setTimeout(() => {
      func.apply(this, args);
    }, wait);
  };
}