reactjs - 为什么这个组件在转换为 React-Hooks 时不起作用？（对此状态和解构部分感到困惑）

Question

基本上试图为预订引擎创建自动完成功能代码在类组件中想要将其转换为具有 React Hooks 的功能组件。尝试转换但我的代码显示了几个警告。如果需要，可以提供任何代码片段。（如何转换 this.state 并解构 this 关键字）

从“反应”导入反应，{组件，片段}；从“prop-types”导入 PropTypes；

class AutocompleteClass extends Component {
  static propTypes = {
    suggestions: PropTypes.instanceOf(Array)
  };

  static defaultProps = {
    suggestions: []
  };

  constructor(props) {
    super(props);

    this.state = {
      // The active selection's index
      activeSuggestion: 0,
      // The suggestions that match the user's input
      filteredSuggestions: [],
      // Whether or not the suggestion list is shown
      showSuggestions: false,
      // What the user has entered
      userInput: ""
    };
  }

  onChange = e => {
    const { suggestions } = this.props;
    const userInput = e.currentTarget.value;

    // Filter our suggestions that don't contain the user's input
    const filteredSuggestions = suggestions.filter(
      suggestion =>
        suggestion.toLowerCase().indexOf(userInput.toLowerCase()) > -1
    );

    this.setState({
      activeSuggestion: 0,
      filteredSuggestions,
      showSuggestions: true,
      userInput: e.currentTarget.value
    });
  };

  onClick = e => {
    this.setState({
      activeSuggestion: 0,
      filteredSuggestions: [],
      showSuggestions: false,
      userInput: e.currentTarget.innerText
    });
  };

  onKeyDown = e => {
    const { activeSuggestion, filteredSuggestions } = this.state;

    // User pressed the enter key
    if (e.keyCode === 13) {
      this.setState({
        activeSuggestion: 0,
        showSuggestions: false,
        userInput: filteredSuggestions[activeSuggestion]
      });
    }
    // User pressed the up arrow
    else if (e.keyCode === 38) {
      if (activeSuggestion === 0) {
        return;
      }

      this.setState({ activeSuggestion: activeSuggestion - 1 });
    }
    // User pressed the down arrow
    else if (e.keyCode === 40) {
      if (activeSuggestion - 1 === filteredSuggestions.length) {
        return;
      }

      this.setState({ activeSuggestion: activeSuggestion + 1 });
    }
  };

  render() {
    const {
      onChange,
      onClick,
      onKeyDown,
      state: {
        activeSuggestion,
        filteredSuggestions,
        showSuggestions,
        userInput
      }
    } = this;

    let suggestionsListComponent;

    if (showSuggestions && userInput) {
      if (filteredSuggestions.length) {
        suggestionsListComponent = (
          <ul class="suggestions">
            {filteredSuggestions.map((suggestion, index) => {
              let className;

              // Flag the active suggestion with a class
              if (index === activeSuggestion) {
                className = "suggestion-active";
              }

              return (
                <li className={className} key={suggestion} onClick={onClick}>
                  {suggestion}
                </li>
              );
            })}
          </ul>
        );
      } else {
        suggestionsListComponent = (
          <div class="no-suggestions">
            <em>No suggestions, you're on your own!</em>
          </div>
        );
      }
    }

    return (
      <Fragment>
        <input
          type="text"
          onChange={onChange}
          onKeyDown={onKeyDown}
          value={userInput}
        />
        {suggestionsListComponent}
      </Fragment>
    );
  }
}

export default AutocompleteClass;

标签： reactjsreact-hooks