从父组件状态填充无状态子组件道具以在 React 中显示嵌套无序列表（使用 Firebase）

Question

我可能在这里遗漏了一些非常简单的东西，但我无法将我的代码正确地运行。我正在尝试为每个 referenceList 显示 referenceListItems 的嵌套无序列表。我想主要的问题是如何将状态变量 referenceListItems 传递给子组件 ReferenceListItems?

const ReferencePage = () => (
  <div>
    <h1>Reference</h1>
    <Reference />
  </div>
);

class ReferenceBase extends Component {
  constructor(props) {
    super(props);
    this.state = {
      loading: false,
      referenceLists: [],
      referenceListItems: [],
    };
  }

  componentDidMount() {
    this.onListenForReferenceLists();
    this.onListenForReferenceListItems();
  }

  onListenForReferenceLists() {
    this.setState({ loading: true });

    this.unsubscribeReferenceLists = this.props.firebase
      .referenceLists()
      .onSnapshot(snapshot => {
        if (snapshot.size) {
          let referenceLists = [];
          snapshot.forEach(doc =>
            referenceLists.push({ ...doc.data(), uid: doc.id }),
          );
          this.setState({
            referenceLists: referenceLists,
            loading: false
          });
        } else {
          this.setState({ referenceLists: null, loading: false });
        }
    });
  }

  onListenForReferenceListItems() {
    this.unsubscribeReferenceListsItems = this.props.firebase
      .referenceListItems()
      .onSnapshot(snapshot => {
        if (snapshot.size) {
          let referenceListItems = [];
          snapshot.forEach(doc =>
            referenceListItems.push({ ...doc.data(), uid: doc.id }),
          );
          this.setState({
            referenceListItems: referenceListItems,
            loading: false
          });
        } else {
          this.setState({ referenceListItems: null, loading: false });
        }
    });
  }

  componentWillUnmount() {
    this.unsubscribeReferenceLists();
    this.unsubscribeReferenceListsItems();
  }

  render() {
    const { referenceLists, referenceListItems, loading } = this.state;
    return (
      <div>
        {loading && <div>Loading ...</div>}
        {referenceLists ? (
          <ReferenceLists referenceLists={referenceLists} />
        ):(
          <div>There are no reference items ...</div>
        )}
      </div>
    );
  }
}

const Reference = withFirebase(ReferenceBase);

const ReferenceLists = ({ referenceLists }) => (
  <ul className="reference-lists">
    {referenceLists.map( referenceList => (
      <ReferenceList key={referenceList.uid} referenceList={referenceList} />
    ))}
  </ul>
);

const ReferenceList = ({ referenceList }) => (
  <li className="reference">
    <strong>{referenceList.userId}</strong> {referenceList.name}
    <ReferenceListItems />
  </li>
);

const ReferenceListItems =({ referenceListItems }) => (
  <ul className="reference-list-items">
    {referenceListItems.map( referenceListItem => (
      <ReferenceListItem key={referenceListItem.uid} referenceListItem={referenceListItem} />
    ))}
  </ul>
);

const ReferenceListItem = ({ referenceListItem }) => (
  <li className="reference-list-item">
    <strong>{referenceListItem.userId}</strong> {referenceListItem.name}
  </li>
);

Answer 1

通过重新声明 referenceList

let referenceLists = [];

它永远不会在您的 class 中设置。您需要 return 闭包内的 referenceLists 或在回调

中设置 class level 变量

this.referenceLists.push({ ...doc.data(), uid: doc.id })

Answer 2

您没有在父 ReferenceBase 组件中明确使用您的 ReferenceListItems。所以你只需要将它作为属性传递到整个组件树中。

  render() {
    const { referenceLists, referenceListItems, loading } = this.state;
    return (
      <div>
        {loading && <div>Loading ...</div>}
        {referenceLists ? (
          <ReferenceLists referenceLists={referenceLists} referenceListItems={referenceListItems} />
        ):(
          <div>There are no reference items ...</div>
        )}
      </div>
    );

参考文献

const ReferenceLists = ({ referenceLists, referenceListItems }) => (
  <ul className="reference-lists">
    {referenceLists.map( referenceList => (
      <ReferenceList key={referenceList.uid} referenceList={referenceList} referenceListItems={referenceListItems} />
    ))}
  </ul>

参考列表

const ReferenceList = ({ referenceList, referenceListItems }) => (
  <li className="reference">
    <strong>{referenceList.userId}</strong> {referenceList.name}
    <ReferenceListItems referenceListItems={referenceListItems}/>
  </li>
);

从父组件状态填充无状态子组件道具以在 React 中显示嵌套无序列表（使用 Firebase）

Populating stateless child component props from parent component state to display nested unordered list in React (with Firebase)

state

reactjs

react-props

参考文献

参考列表