Lodash 去抖动并没有像预期的那样阻止调度 onChange [英] Lodash debounce isn't preventing dispatch as expected onChange

问题描述

目前，我有一个复选框列表，onChange 将向服务器发出请求以返回一些数据.但是，只有当用户在一段时间后停止选择多复选框时，我才使用 lodash debounce 尝试发出请求.

Currently, I have a list of checkboxes that onChange will make a request to the server to return some data. However, I am using lodash debounce to try and make a request only when the user has stopped selecting the multi-checkbox after a certain amount of time.

目前，它会阻止立即分派，但会在达到去抖动时间后分派，而不是在用户停止与复选框交互时分派.有人能告诉我我将如何实现这一目标或我哪里出错了吗?

Currently, it prevents dispatching straight away but will dispatch after the debounce time has met rather when the user has stopped interacting with the checkboxes. Can someone tell me how I would achieve this or where I am going wrong?

谢谢！

import React, { useContext, useState, useEffect } from 'react';
import { Context } from '../../pages/search-and-results/search-and-results.js';
import debounce from 'lodash.debounce';

const FilterCheckbox = ({ name, value }) => {
  const checkboxContext = useContext(Context);
  const [checked, setChecked] = useState(false);
  const debounceCheckboxSelection = debounce(dispatchCheckbox, 2000);

  function dispatchCheckbox(type, value) {
    checkboxContext.dispatch({
      type: type,
      payload: { value }
    });
  }

  return (
    <Label>
      <FilterInput
        type="checkbox"
        name={name}
        onChange={() => {
          if (checked) {
            debounceCheckboxSelection('REMOVE_SELECTED_PROPERTY_TYPE', value);
            setChecked(false);
            return;
          }
          debounceCheckboxSelection('SET_SELECTED_PROPERTY_TYPE', value);
          setChecked(true);
        }}
        checked={checked}
      />
      {name}
    </Label>
  );
};

export default FilterCheckbox;

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>

推荐答案

每次重新渲染时都会创建去抖动函数，以修复它:

Your debounced function is getting created at each re-render, to fix it:

您可以使用 useRef 返回将在组件的整个生命周期内持续存在的 ref 对象:

You can use useRef which returns a ref object which will persist for the full lifetime of the component:

const debounceCheckboxSelection = useRef(
  debounce(dispatchCheckbox, 2000);
)

并使用 debounceCheckboxSelection.current 访问其初始值:

and access its initial value with debounceCheckboxSelection.current:

<FilterInput
  type="checkbox"
  name={name}
  onChange={() => {
    if (checked) {
      debounceCheckboxSelection.current('REMOVE_SELECTED_PROPERTY_TYPE', value);
      setChecked(false);
      return;
    }
    debounceCheckboxSelection.current('SET_SELECTED_PROPERTY_TYPE', value);
    setChecked(true);
  }}
  checked={checked}
/>

或者你可以使用 useCallback返回回调的记忆版本，该版本仅在其任何依赖项更改时才会更改:

Or you can use useCallback will returns a memoized version of the callback that only changes when any of its dependencies change:

const debounceCheckboxSelection = useCallback(
  () => debounce(dispatchCheckbox, 2000), []
)

这篇关于Lodash 去抖动并没有像预期的那样阻止调度 onChange的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！