我将使用这个例子http://codepen.io/lacker/pen/vXpAgj,因为它与我目前的问题非常相似。所以,假设我们有这个数组:React array.map()
[
{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'}
]
如何使用array.map()重写下面的代码?
var rows = [];
var lastCategory = null;
this.props.products.forEach(function(product) {
if (product.category !== lastCategory) {
rows.push(<ProductCategoryRow category={product.category} key={product.category} />);
}
rows.push(<ProductRow product={product} key={product.name} />);
lastCategory = product.category;
});
下面的示例不能正确地完成这项工作。
const lastCategory = null;
const rows = this.props.products.map(function(product){
if (product.category !== lastCategory) {
return (<ProductCategoryRow category={product.category} key={product.category} />);
}
return (<ProductRow product={product} key={product.name} />);
lastCategory = product.category;
});
欢呼和感谢,
由于上面的返回结果,你永远不会到达'lastCategory = product.category'行 – larz