react经典进阶demo

这是我在官方文档上看到的,功能是实现(具体是什么，请往下看)

以下是json数据:

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

显示红色的物品，是没有库存的(stocked:false),如$29.99的basketball和$399.99的iphone5。

在我看来react的结构就像‘包饺子’，一层夹着一层，可以看一下上图的几个边框，不同颜色代表着不同区域划分。

1.(orange): contains the entirety of the example 外边的黄色区域，包含整个例子。

2.(blue): receives all user input  里面一层的蓝色框框，度用户的输入进行serach。

3.(green): displays and filters the data collection based onuser input   绿色框展示用户筛选的物品信息。

4. (turquoise): displays a heading for each category  显示产品种类，这里是sproting goods和electronics。

5.(red): displays a row for each product  红色框，每件物品。

//这是结构的最外一层  它里面包含searchBar和producTable两个组件
var FilterableProductTable = React.createClass({
  render: function() {
    return (
      <div>
        <SearchBar /> 
        <ProductTable products={this.props.products} />
      </div>
    );
  }
});


var PRODUCTS = [
  {category: 'Sporting Goods', price: '$49.99', stocked: true, name: 'Football'},
  {category: 'Sporting Goods', price: '$9.99', stocked: true, name: 'Baseball'},
  {category: 'Sporting Goods', price: '$29.99', stocked: false, name: 'Basketball'},
  {category: 'Electronics', price: '$99.99', stocked: true, name: 'iPod Touch'},
  {category: 'Electronics', price: '$399.99', stocked: false, name: 'iPhone 5'},
  {category: 'Electronics', price: '$199.99', stocked: true, name: 'Nexus 7'}
];
 //这里的prop属性定义了product  引用字上面的json数据
ReactDOM.render(
  <FilterableProductTable products={PRODUCTS} />,
  document.getElementById('container')
);

//这是最简单的搜索框组件
var SearchBar = React.createClass({
  render: function() {
    return (
      <form>
        <input type="text" placeholder="Search..." />
        <p>
          <input type="checkbox" />
          {' '}
          Only show products in stock
        </p>
      </form>
    );
  }
});

//关键的来了  这个productTable里面还包含了一些组件
var ProductTable = React.createClass({
  render: function() {
    var rows = [];
    var lastCategory = null;
    //遍历json数据
    this.props.products.forEach(function(product) {
      if (product.category !== lastCategory) {  //注意这里的判断，并不是每回都要把类别加一次
       //这里有一个产品种类的组件
      rows.push(<ProductCategoryRow category={product.category} key={product.category} />);
      }
      //还有一个产品行的组件   
      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>
    );
  }
});

//category在上面可以找到
var ProductCategoryRow = React.createClass({
  render: function() {
    return (<tr><th colSpan="2">{this.props.category}</th></tr>);
  }
});

var ProductRow = React.createClass({
  render: function() {
    //如果没有货存  红色字体显示
   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>
    );
  }
});

就这样玩了吗？还没有，以上还没实现搜索和过滤功能。

var ProductCategoryRow = React.createClass({
  render: function() {
    return (<tr><th colSpan="2">{this.props.category}</th></tr>);
  }
});

var ProductRow = React.createClass({
  render: function() {
    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>
    );
  }
});   //这里都没变

//注意这里有改动 
var ProductTable = React.createClass({
  render: function() {
    var rows = [];
    var lastCategory = null;
    this.props.products.forEach(function(product) {
    //用于过滤产品(用户输入的关键字和库存)
      if (product.name.indexOf(this.props.filterText) === -1 || (!product.stocked && this.props.inStockOnly)) { //注意此处的逻辑
        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;
    }.bind(this));  //由于函数里面用到了this  这里bind一下
    return (
      <table>
        <thead>
          <tr>
            <th>Name</th>
            <th>Price</th>
          </tr>
        </thead>
        <tbody>{rows}</tbody>
      </table>
    );
  }
});

//serachBar现在膨胀了  这么多
var SearchBar = React.createClass({
  handleChange: function() {
     //上面肯定有个函数  肯定在父组件上
      this.props.onUserInput(
      this.refs.filterTextInput.value,
      this.refs.inStockOnlyInput.checked  //注意这里的ref用法
    );
  },
  render: function() {
    return (
      <form>
        <input
          type="text"
          placeholder="Search..."
          value={this.props.filterText}
          ref="filterTextInput"
          onChange={this.handleChange} //文本改变回调事件  它的作用是什么？  下面有答案
        />
        <p>
          <input
            type="checkbox"
            checked={this.props.inStockOnly}
            ref="inStockOnlyInput"
            onChange={this.handleChange} //checkbox的判断
          />
          {' '}
          Only show products in stock
        </p>
      </form>
    );
  }
});

//关键的来了   这个里面就是饺子皮
var FilterableProductTable = React.createClass({
  getInitialState: function() {
    return {
      filterText: '',
      inStockOnly: false
    };
  },  //这里初始化的state  文本为空  默认checkbox=false

  handleUserInput: function(filterText, inStockOnly) {
    this.setState({
      filterText: filterText,
      inStockOnly: inStockOnly
    });
  },

  render: function() {
    return (
      <div>
        <SearchBar
         //prop定义的的位置  可以对照着看
          filterText={this.state.filterText}
          inStockOnly={this.state.inStockOnly}
          onUserInput={this.handleUserInput} //这个函数用于改变初始state
        />
        //prop定义的位置  要注意这里的ProductTable里面的filterText和instockOnly  是随着serachBar的输入变动的
        <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', stocked: true, name: 'Baseball'},
  {category: 'Sporting Goods', price: '$29.99', stocked: false, name: 'Basketball'},
  {category: 'Electronics', price: '$99.99', stocked: true, name: 'iPod Touch'},
  {category: 'Electronics', price: '$399.99', stocked: false, name: 'iPhone 5'},
  {category: 'Electronics', price: '$199.99', stocked: true, name: 'Nexus 7'}
];

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

好了，代码量并不大，但是这里面的逻辑和每层之间的关系确实有点搞人呀。。。希望大家看懂了react想表达的是什么