从 firebase.firestore.Timestamp.now() 中减去一周？

作为定义在这里，

firebase.firestore.Timestamp.now()

相当于

firebase.firestore.Timestamp.fromMillis(Date.now())

要获得一周前的时间戳，您可以使用：

// 1 week in ms = 1000 * 60 * 60 * 24 * 7 = 604800000

const nowTimestamp = firebase.firestore.Timestamp.now();
const weekOldTimestamp = firebase.firestore.Timestamp.fromMillis(nowTimestamp.toMillis() - 604800000);
// or the shorter
const weekOldTimestamp = firebase.firestore.Timestamp.fromMillis(Date.now() - 604800000);

假设您在名为 的集合中有以下文档/photos：

{
  "title": "My Photo",
  "desc": "This is the first photo I uploaded here",
  "storageRef": "/userData/userid1/uploads/89q24u2q98y23.png",
  "thumbnailRef": "/userData/userid1/uploads/89q24u2q98y23.thumbnail.png",
  "createdAt": FieldValue.serverTimestamp(),
}

如果要查找一周前的所有照片，可以使用以下相同语句之一：

firebase.firestore().collection("photos")
  .where("createdAt", "<", new Date(Date.now() - 604800000))
  .get()

或

const weekAgoTimestamp = firebase.firestore.Timestamp.fromMillis(Date.now() - 604800000);

firebase.firestore().collection("photos")
  .where("createdAt", "<", weekAgoTimestamp)
  .get()

如果您已经拥有该文档的副本，请从这样的查询中获取：

const aPhotoSnapshot = await firebase.firestore()
  .doc("photos/somePhotoId")
  .get();

并且您想检查它是否超过一周，您可以使用：

const createdAtTimestamp = aPhotoSnapshot.get("createdAt");
const isWeekOld = createdAtTimestamp.toMillis() < Date.now() - 604800000;