我在看Pluralsight关于React的课程,老师说道具不应该被改变。我现在正在读一篇关于道具vs.国家的文章(uberVU/react-guide),它说

道具和状态更改都会触发呈现更新。

文章后面说:

Props(属性的缩写)是组件的配置,如果可以的话,是它的选项。它们是从上面接收的,是不可变的。

所以道具可以改变,但它们应该是不可变的? 什么时候应该使用道具,什么时候应该使用状态? 如果你有一个React组件需要的数据,它应该通过道具或设置在React组件通过getInitialState?


当前回答

在react中,我们通常使用模块来分离组件。有时分离的组件需要在它们内部共享数据。如果父组件有一些数据应该在子组件上共享,那么道具是解决方案。我们可以使用从父母到孩子的道具共享数据。Props是不可变的,这意味着您不能更改数据。

另一方面,状态用于跟踪数据中的任何变化。您可以将状态视为数据的存储和可以更新该数据的函数。状态是可变的。您可以在同一组件中使用setState函数更改状态

其他回答

基本上,区别在于状态类似于OOP中的属性:它是类(组件)的局部属性,用于更好地描述它。道具就像参数一样——它们从组件的调用者(父组件)传递给组件:就像你调用一个带有特定参数的函数一样。

简而言之。

道具值不能改变[不可变] 使用setState方法[mutable]可以改变状态值

亲子交流,只需传递道具即可。

使用state在控制器视图中存储当前页面所需的数据。

使用道具将数据和事件处理程序传递给你的子组件。

这些列表应该有助于指导您在组件中处理数据。

道具

是不可变的 它可以让React进行快速参考检查 用于从视图控制器向下传递数据 顶级组件 有更好的表现 使用它将数据传递给子组件

状态

是否应该在视图控制器中进行管理 顶级组件 是可变的 表现更差 不应该从子组件访问 用道具把它传下去

For communication between two components that don't have a parent-child relationship, you can set up your own global event system. Subscribe to events in componentDidMount(), unsubscribe in componentWillUnmount(), and call setState() when you receive an event. Flux pattern is one of the possible ways to arrange this. - https://facebook.github.io/react/tips/communicate-between-components.html What Components Should Have State? Most of your components should simply take some data from props and render it. However, sometimes you need to respond to user input, a server request or the passage of time. For this you use state. Try to keep as many of your components as possible stateless. By doing this you'll isolate the state to its most logical place and minimize redundancy, making it easier to reason about your application. A common pattern is to create several stateless components that just render data, and have a stateful component above them in the hierarchy that passes its state to its children via props. The stateful component encapsulates all of the interaction logic, while the stateless components take care of rendering data in a declarative way. - https://facebook.github.io/react/docs/interactivity-and-dynamic-uis.html#what-components-should-have-state What Should Go in State? State should contain data that a component's event handlers may change to trigger a UI update. In real apps this data tends to be very small and JSON-serializable. When building a stateful component, think about the minimal possible representation of its state, and only store those properties in this.state. Inside of render() simply compute any other information you need based on this state. You'll find that thinking about and writing applications in this way tends to lead to the most correct application, since adding redundant or computed values to state means that you need to explicitly keep them in sync rather than rely on React computing them for you. - https://facebook.github.io/react/docs/interactivity-and-dynamic-uis.html#what-should-go-in-state

React组件使用state来读取/写入内部变量,这些变量可以通过以下方式更改/突变:

this.setState({name: 'Lila'})

React props是一个特殊的对象,允许程序员从父组件中获取变量和方法到子组件中。

它有点像房子的门窗。道具也是不可变的子组件不能改变/更新他们。

当父组件更改道具时,有几个方法可以帮助监听。

props是JavaScript对象,传递给组件,保存配置属性。 props是接收组件不可更改的 state是在Component中管理的JavaScript对象,保存它的内部状态。 更新可以触发重新渲染