PlatformLocationlink

说明link

PlatformLocation encapsulates all calls to DOM apis, which allows the Router to be platform agnostic. This means that we can have different implementation of PlatformLocation for the different platforms that angular supports. For example, @angular/platform-browser provides an implementation specific to the browser environment, while @angular/platform-webworker provides one suitable for use with web workers.

The PlatformLocation class is used directly by all implementations of LocationStrategywhen they need to interact with the DOM apis like pushState, popState, etc...

in turn is used by the Locationservice which is used directly by the Routerin order to navigate between routes. Since all interactions between Router/ Location/ LocationStrategyand DOM apis flow through the PlatformLocation class they are all platform independent.