好.因此，我从非常有帮助的Google开发人员那里获得了一些帮助.

Ok. So I got some assistance from a very helpful Google developer.

这最终奏效了.

var beginningDate = Date.now() - 604800000;
var beginningDateObject = new Date(beginningDate);

db.collection("****")
    .where('display', '==', true)
    .where('createdAt', '>', beginningDateObject)
    .get()
    .then(function(querySnapshot) {console.log(/* ... */)});