从父组件状态填充无状态子组件属性，以在 React 中显示嵌套的无序列表(使用 Firebase)

Question

我可能在这里错过了一些非常简单的东西，但我无法让我的代码正常运行。我正在尝试为每个referenceList显示嵌套的无referenceListItems列表。我想的主要问题是如何将状态变量referenceListItems传递到子组件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

您不会在父组件ReferenceBase组件中显式使用ReferenceListItems。因此，您只需将其作为属性传递到整个组件树中即可。

  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>
    );

参考列表

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>
);

Answer 2

通过重新声明 referenceList

let referenceLists = [];

它永远不会在你的类中设置。 你要么需要在闭包中返回 referenceLists，要么在你的回调中设置类级变量

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