如何在React.js中执行debounce ?

我想撤消handleOnChange。

我尝试debounce(这。handleOnChange, 200)但它不起作用。

function debounce(fn, delay) {
  var timer = null;
  return function() {
    var context = this,
      args = arguments;
    clearTimeout(timer);
    timer = setTimeout(function() {
      fn.apply(context, args);
    }, delay);
  };
}

var SearchBox = React.createClass({
  render: function() {
    return <input type="search" name="p" onChange={this.handleOnChange} />;
  },

  handleOnChange: function(event) {
    // make ajax call
  }
});

当前回答

如果我们有兴趣在react.js中使用epic.js,我们可以在epic.js库中使用debounceTime rxjs/操作符。因此,我们可以在epic.js的帮助下,在react.js中使用可观察对象,而不是使用回调。

其他回答

只是最近react和lodash的另一个变体。

class Filter extends Component {
  static propTypes = {
    text: PropTypes.string.isRequired,
    onChange: PropTypes.func.isRequired
  }

  state = {
    initialText: '',
    text: ''
  }

  constructor (props) {
    super(props)

    this.setText = this.setText.bind(this)
    this.onChange = _.fp.debounce(500)(this.onChange.bind(this))
  }

  static getDerivedStateFromProps (nextProps, prevState) {
    const { text } = nextProps

    if (text !== prevState.initialText) {
      return { initialText: text, text }
    }

    return null
  }

  setText (text) {
    this.setState({ text })
    this.onChange(text)
  }

  onChange (text) {
    this.props.onChange(text)
  }

  render () {
    return (<input value={this.state.text} onChange={(event) => this.setText(event.target.value)} />)
  }
}

你也可以使用自己编写的mixin,就像这样:

var DebounceMixin = {
  debounce: function(func, time, immediate) {
    var timeout = this.debouncedTimeout;
    if (!timeout) {
      if (immediate) func();
      this.debouncedTimeout = setTimeout(function() {
        if (!immediate) func();
        this.debouncedTimeout = void 0;
      }.bind(this), time);
    }
  }
};

然后像这样在你的组件中使用它:

var MyComponent = React.createClass({
  mixins: [DebounceMixin],
  handleClick: function(e) {
    this.debounce(function() {
      this.setState({
        buttonClicked: true
      });
    }.bind(this), 500, true);
  },
  render: function() {
    return (
      <button onClick={this.handleClick}></button>
    );
  }
});

使用React Hooks和响应式编程(RxJS)的React ajax debounce和cancel示例解决方案:

import React, { useEffect, useState } from "react";
import { ajax } from "rxjs/ajax";
import { debounceTime, delay, takeUntil } from "rxjs/operators";
import { Subject } from "rxjs/internal/Subject";

const App = () => {
  const [items, setItems] = useState([]);
  const [loading, setLoading] = useState(true);
  const [filterChangedSubject] = useState(() => {
    // Arrow function is used to init Singleton Subject. (in a scope of a current component)
    return new Subject<string>();
  });

  useEffect(() => {
    // Effect that will be initialized once on a react component init.
    const subscription = filterChangedSubject
      .pipe(debounceTime(200))
      .subscribe((filter) => {
        if (!filter) {
          setLoading(false);
          setItems([]);
          return;
        }
        ajax(`https://swapi.dev/api/people?search=${filter}`)
          .pipe(
            // current running ajax is canceled on filter change.
            takeUntil(filterChangedSubject)
          )
          .subscribe(
            (results) => {
              // Set items will cause render:
              setItems(results.response.results);
            },
            () => {
              setLoading(false);
            },
            () => {
              setLoading(false);
            }
          );
      });

    return () => {
      // On Component destroy. notify takeUntil to unsubscribe from current running ajax request
      filterChangedSubject.next("");
      // unsubscribe filter change listener
      subscription.unsubscribe();
    };
  }, []);

  const onFilterChange = (e) => {
    // Notify subject about the filter change
    filterChangedSubject.next(e.target.value);
  };
  return (
    <div>
      Cards
      {loading && <div>Loading...</div>}
      <input onChange={onFilterChange}></input>
      {items && items.map((item, index) => <div key={index}>{item.name}</div>)}
    </div>
  );
};

export default App;

FYI

这是另一个PoC实现:

没有任何库(例如lodash)用于debound 使用React Hooks API

我希望它能帮助你:)

import React, { useState, useEffect, ChangeEvent } from 'react';

export default function DebouncedSearchBox({
  inputType,
  handleSearch,
  placeholder,
  debounceInterval,
}: {
  inputType?: string;
  handleSearch: (q: string) => void;
  placeholder: string;
  debounceInterval: number;
}) {
  const [query, setQuery] = useState<string>('');
  const [timer, setTimer] = useState<NodeJS.Timer | undefined>();

  useEffect(() => {
    if (timer) {
      clearTimeout(timer);
    }
    setTimer(setTimeout(() => {
      handleSearch(query);
    }, debounceInterval));
  }, [query]);

  const handleOnChange = (e: ChangeEvent<HTMLInputElement>): void => {
    setQuery(e.target.value);
  };

  return (
    <input
      type={inputType || 'text'}
      className="form-control"
      placeholder={placeholder}
      value={query}
      onChange={handleOnChange}
    />
  );
}

Julen的解决方案有点难以阅读,这里有更清晰和准确的反应代码,供那些根据标题而不是问题的微小细节绊倒他的人使用。

Tl;dr版本:当你要更新到观察者发送调用一个调度方法,反过来实际上会通知观察者(或执行ajax等)

使用示例组件jsfiddle完成jsfiddle

var InputField = React.createClass({

    getDefaultProps: function () {
        return {
            initialValue: '',
            onChange: null
        };
    },

    getInitialState: function () {
        return {
            value: this.props.initialValue
        };
    },

    render: function () {
        var state = this.state;
        return (
            <input type="text"
                   value={state.value}
                   onChange={this.onVolatileChange} />
        );
    },

    onVolatileChange: function (event) {
        this.setState({ 
            value: event.target.value 
        });

        this.scheduleChange();
    },

    scheduleChange: _.debounce(function () {
        this.onChange();
    }, 250),

    onChange: function () {
        var props = this.props;
        if (props.onChange != null) {
            props.onChange.call(this, this.state.value)
        }
    },

});