javascript react-native 中 `this` 的上下文

Question

我在这里关注 react-navigation navigator tutorial 并且对使用 this.navigator = nav

设置 this.navigator 的方式感到困惑

完整代码如下：

import { NavigationActions } from 'react-navigation';

const AppNavigator = StackNavigator(SomeAppRouteConfigs);

class App extends React.Component {
  someEvent() {
    // call navigate for AppNavigator here:
    this.navigator && this.navigator.dispatch(
      NavigationActions.navigate({ routeName: someRouteName })
    );
  }
  render() {
    return (
      <AppNavigator ref={nav => { this.navigator = nav; }} />
    );
  }
}

根据我的理解（至少对于[=29=以外的编程语言]，<AppNavigator ref={nav => { this.navigator = nav; }} />中的this应该是指AppNavigator，因此，代码如何在 someEvent 中似乎访问了由该代码设置的相同 this.navigator？

任何线索将不胜感激。提前致谢！

Answer 1

An arrow function expression has a shorter syntax than a function expression and does not bind its own this

from MDN

因此 this 绑定到 App，这解释了行为。

javascript react-native 中 `this` 的上下文

context of `this` in javascript react-native

javascript

react-native

react-navigation