Lodash debounce isn't preventing dispatch as expected onChange

问题

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.

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?

Thanks!

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>

回答1:

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

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);
)

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}
/>

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), []
)

来源：https://stackoverflow.com/questions/62212641/lodash-debounce-isnt-preventing-dispatch-as-expected-onchange

标签

reactjs

debounce

debouncing