內容參考github ts問題11085
DomRect之前叫ClientRect,後來更名了1,
ts兼容了兩種對象,但ClientRect沒有x,y屬性。所以使用getBoundingClientRect時:
let unspecifiedRect = document.body.getBoundingClientRect();
unspecifiedRect.x // fails
let domRect = document.body.getBoundingClientRect() as DOMRect;
domRect.x // works