Geolocation GeolocationAPI扩展了Web规范:https://developer.mozilla.org/en-US/docs/Web/API/Geolocation 作为浏览器的
XMLHttpRequest,fetch {set,clear}{Timeout,Interval,Immediate},{request,cancel}AnimationFrame navigator.geolocation
theconsumersubscribes.const{next,error}=observer;letwatchId; //SimplegeolocationAPIcheckprovidesvaluestopublishif('geolocation'innavigator