Clock examples use impure `.toLocaleTimeString()`

The new React Docs have various "Clock" examples and challenges throughout the page. All of them use .toLocaleTimeString() (without arguments!) to output the time. This is a bit strange, especially as an example on the page "Keeping Components Pure":

While .getHours() will always return the same value if the Date object is the same, the whole point of .toLocaleTimeString() with no locale specified is that it's impure, its return value depending on external state outside React: the configured environment locale.

If you scroll just a little bit upwards on the page "Keeping Components Pure", you'll find

Your components could run in a different environment—for example, on the server!

as one of the reasons for why React cares about component purity. But that example is very likely to break with .toLocaleTimeString(), as chances are that the server has a different default locale than the user's browser.

My suggestion would be to pass a language prop to the Clock component, so Clock itself is actually pure, but App (which isn't a visible part of the example) can do <Clock time={time} language={navigator.language} />, keeping the nice behavior of localized examples: https://codesandbox.io/s/sandpack-project-forked-43udl3?file=/Clock.js

在新的 React Docs 中搜索 Clock 示例，并查看“Keeping Components Pure”挑战以及链接的 Clock.js 示例。更新这些示例，使 Clock 接收语言上下文，同时保留本地化输出，然后验证页面上的所有 Clock 示例都遵循相同的模式。