diff --git a/content/docs/fragments.md b/content/docs/fragments.md index 04de0463bc..9924ce3a3f 100644 --- a/content/docs/fragments.md +++ b/content/docs/fragments.md @@ -4,7 +4,7 @@ title: Fragments permalink: docs/fragments.html --- -A common pattern in React is for a component to return multiple elements. Fragments let you group a list of children without adding extra nodes to the DOM. +React 中的一个常见模式是一个组件返回多个元素。Fragments 允许你将子列表分组,而无需向 DOM 添加额外节点。 ```js render() { @@ -18,11 +18,11 @@ render() { } ``` -There is also a new [short syntax](#short-syntax) for declaring them, but it isn't supported by all popular tools yet. +还有一种新的[短语法](#short-syntax)可用于声明它们,但尚未得到所有流行工具的支持。 -## Motivation {#motivation} +## 动机 {#motivation} -A common pattern is for a component to return a list of children. Take this example React snippet: +一种常见模式是组件返回一个子元素列表。以此 React 代码片段为例: ```jsx class Table extends React.Component { @@ -38,7 +38,7 @@ class Table extends React.Component { } ``` -`<Columns />` would need to return multiple `<td>` elements in order for the rendered HTML to be valid. If a parent div was used inside the `render()` of `<Columns />`, then the resulting HTML will be invalid. +`<Columns />` 需要返回多个 `<td>` 元素以使渲染的 HTML 有效。如果在 `<Columns />` 的 `render()` 中使用了父 div,则生成的 HTML 将无效。 ```jsx class Columns extends React.Component { @@ -53,7 +53,7 @@ class Columns extends React.Component { } ``` -results in a `<Table />` output of: +得到一个 `<Table />` 输出: ```jsx <table> @@ -66,9 +66,9 @@ results in a `<Table />` output of: </table> ``` -Fragments solve this problem. +Fragments 解决了这个问题。 -## Usage {#usage} +## 用法 {#usage} ```jsx{4,7} class Columns extends React.Component { @@ -83,7 +83,7 @@ class Columns extends React.Component { } ``` -which results in a correct `<Table />` output of: +这样可以正确的输出 `<Table />`: ```jsx <table> @@ -94,9 +94,9 @@ which results in a correct `<Table />` output of: </table> ``` -### Short Syntax {#short-syntax} +### 短语法 {#short-syntax} -There is a new, shorter syntax you can use for declaring fragments. It looks like empty tags: +你可以使用一种新的,且更简短的语法来声明 Fragments。它看起来像空标签: ```jsx{4,7} class Columns extends React.Component { @@ -111,20 +111,20 @@ class Columns extends React.Component { } ``` -You can use `<></>` the same way you'd use any other element except that it doesn't support keys or attributes. +你可以像使用任何其他元素一样使用 `<> </>`,除了它不支持 key 或属性。 -Note that **[many tools don't support it yet](/blog/2017/11/28/react-v16.2.0-fragment-support.html#support-for-fragment-syntax)** so you might want to explicitly write `<React.Fragment>` until the tooling catches up. +请注意 **[目前许多工具尚不支持](/blog/2017/11/28/react-v16.2.0-fragment-support.html#support-for-fragment-syntax)** ,所以直到工具支持之前,你可能要显式的使用 `<React.Fragment>`。 -### Keyed Fragments {#keyed-fragments} +### 带 key 的 Fragments {#keyed-fragments} -Fragments declared with the explicit `<React.Fragment>` syntax may have keys. A use case for this is mapping a collection to an array of fragments -- for example, to create a description list: +使用显式 `<React.Fragment>` 语法声明的片段可能具有 key。一个使用场景是将一个集合映射到一个 Fragments 数组 - 举个例子,创建一个描述列表: ```jsx function Glossary(props) { return ( <dl> {props.items.map(item => ( - // Without the `key`, React will fire a key warning + // 没有`key`,React 会发出一个关键警告 <React.Fragment key={item.id}> <dt>{item.term}</dt> <dd>{item.description}</dd> @@ -135,8 +135,8 @@ function Glossary(props) { } ``` -`key` is the only attribute that can be passed to `Fragment`. In the future, we may add support for additional attributes, such as event handlers. +`key` 是唯一可以传递给 `Fragment` 的属性。未来我们可能会添加对其他属性的支持,例如事件。 -### Live Demo {#live-demo} +### 在线 Demo {#live-demo} -You can try out the new JSX fragment syntax with this [CodePen](https://codepen.io/reactjs/pen/VrEbjE?editors=1000). +你可以在 [CodePen](https://codepen.io/reactjs/pen/VrEbjE?editors=1000) 中尝试这个新的 JSX Fragment 语法。