react 学习笔记

理论学习 + demo产出

class ProductCategoryRow extends React.Component {
  render() {
    return (<tr><th colSpan="2">{this.props.category}</th></tr>);
  }
}

class ProductRow extends React.Component {
  render() {
    var name = this.props.product.stocked ?
      this.props.product.name :
      <span style={{color: 'red'}}>
        {this.props.product.name}
      </span>;
    return (
      <tr>
        <td>{name}</td>
        <td>{this.props.product.price}</td>
      </tr>
    );
  }
}

class ProductTable extends React.Component {
  render() {
    var rows = [];
    var lastCategory = null;
    console.log(this.props.inStockOnly)
    this.props.products.forEach((product) => {
      if (product.name.indexOf(this.props.filterText) === -1 || (!product.stocked && this.props.inStockOnly)) {
        return;
      }
      if (product.category !== lastCategory) {
        rows.push(<ProductCategoryRow category={product.category} key={product.category} />);
      }
      rows.push(<ProductRow product={product} key={product.name} />);
      lastCategory = product.category;
    });
    return (
      <table>
        <thead>
          <tr>
            <th>Name</th>
            <th>Price</th>
          </tr>
        </thead>
        <tbody>{rows}</tbody>
      </table>
    );
  }
}

class SearchBar extends React.Component {
  constructor(props) {
    super(props);
    this.handleFilterTextInputChange = this.handleFilterTextInputChange.bind(this);
    this.handleInStockInputChange = this.handleInStockInputChange.bind(this);
  }
  
  handleFilterTextInputChange(e) {
    this.props.onFilterTextInput(e.target.value);
  }
  
  handleInStockInputChange(e) {
    this.props.onInStockInput(e.target.checked);
  }
  
  render() {
    return (
      <form>
        <input
          type="text"
          placeholder="Search..."
          value={this.props.filterText}
          onChange={this.handleFilterTextInputChange}
        />
        <p>
          <input
            type="checkbox"
            checked={this.props.inStockOnly}
            onChange={this.handleInStockInputChange}
          />
          {' '}
          Only show products in stock
        </p>
      </form>
    );
  }
}

class FilterableProductTable extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      filterText: '',inStockOnly: false
    };
    
    this.handleFilterTextInput = this.handleFilterTextInput.bind(this);
    this.handleInStockInput = this.handleInStockInput.bind(this);
  }

  handleFilterTextInput(filterText) {
    this.setState({
      filterText: filterText
    });
  }
  
  handleInStockInput(inStockOnly) {
    this.setState({
      inStockOnly: inStockOnly
    })
  }

  render() {
    return (
      <div>
        <SearchBar
          filterText={this.state.filterText}
          inStockOnly={this.state.inStockOnly}
          onFilterTextInput={this.handleFilterTextInput}
          onInStockInput={this.handleInStockInput}
        />
        <ProductTable
          products={this.props.products}
          filterText={this.state.filterText}
          inStockOnly={this.state.inStockOnly}
        />
      </div>
    );
  }
}


var PRODUCTS = [
  {category: 'Sporting Goods',price: '$49.99',stocked: true,name: 'Football'},{category: 'Sporting Goods',price: '$9.99',name: 'Baseball'},price: '$29.99',stocked: false,name: 'Basketball'},{category: 'Electronics',price: '$99.99',name: 'iPod Touch'},price: '$399.99',name: 'iPhone 5'},price: '$199.99',name: 'Nexus 7'}
];

ReactDOM.render(
  <FilterableProductTable products={PRODUCTS} />,document.getElementById('container')
);

class CommentList extends React.Component {
  constructor() {
    super();
    this.handleChange = this.handleChange.bind(this);
    this.state = {
      // "DataSource" 就是全局的数据源
      comments: DataSource.getComments()
    };
  }

  componentDidMount() {
    // 添加事件处理函数订阅数据
    DataSource.addChangeListener(this.handleChange);
  }

  componentWillUnmount() {
    // 清除事件处理函数
    DataSource.removeChangeListener(this.handleChange);
  }

  handleChange() {
    // 任何时候数据发生改变就更新组件
    this.setState({
      comments: DataSource.getComments()
    });
  }

  render() {
    return (
      <div>
        {this.state.comments.map((comment) => (
          <Comment comment={comment} key={comment.id} />
        ))}
      </div>
    );
  }
}

class BlogPost extends React.Component {
  constructor(props) {
    super(props);
    this.handleChange = this.handleChange.bind(this);
    this.state = {
      blogPost: DataSource.getBlogPost(props.id)
    };
  }

  componentDidMount() {
    DataSource.addChangeListener(this.handleChange);
  }

  componentWillUnmount() {
    DataSource.removeChangeListener(this.handleChange);
  }

  handleChange() {
    this.setState({
      blogPost: DataSource.getBlogPost(this.props.id)
    });
  }

  render() {
    return <TextBlock text={this.state.blogPost} />;
  }
}

const CommentListWithSubscription = withSubscription(
  CommentList,(DataSource) => DataSource.getComments()
);

const BlogPostWithSubscription = withSubscription(
  BlogPost,(DataSource,props) => DataSource.getBlogPost(props.id)
);
// 函数接受一个组件参数……
function withSubscription(WrappedComponent,selectData) {
  // ……返回另一个新组件……
  return class extends React.Component {
    constructor(props) {
      super(props);
      this.handleChange = this.handleChange.bind(this);
      this.state = {
        data: selectData(DataSource,props)
      };
    }

    componentDidMount() {
      // ……注意订阅数据……
      DataSource.addChangeListener(this.handleChange);
    }

    componentWillUnmount() {
      DataSource.removeChangeListener(this.handleChange);
    }

    handleChange() {
      this.setState({
        data: selectData(DataSource,this.props)
      });
    }

    render() {
      // ……使用最新的数据渲染组件
      // 注意此处将已有的props属性传递给原组件
      return <WrappedComponent data={this.state.data} {...this.props} />;
    }
  };
}

（编辑：李大同）

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