我正尝试从最新消息到最旧消息(从下到上)分页。我的查询有效,但是在查询新消息后,它将以错误的顺序追加数组。我确实关注了this条文章。这是我的逻辑:
//Global variables
let start = null
let end = null
collectionRef
.orderBy('createTimestamp', 'desc')
.limit(10)
.get()
.then(snapshot => {
start = snapshot.docs[snapshot.docs.length - 1]
if (start) {
const listener = collectionRef
.orderBy('createTimestamp')
.startAt(start)
.onSnapshot(messages => {
messages.docChanges().forEach(change => {
const message = this.convertObjectTimestampPropertiesToDate({
id: change.doc.id,
...change.doc.data()
})
if (change.type === 'added') {
store.commit('chats/addMessage', message)
}
})
})
store.commit('chats/setObserver', listener)
}
})
如果我在消息列表的顶部,那么我将启动此功能(这是我的消息顺序出错的部分。它将最大的时间戳项向上移动,将较小的时间戳项向下移动,这是错误的。) :
async getMoreMessages() {
collectionRef
.orderBy('createTimestamp', 'desc')
.startAt(start)
.limit(10)
.get()
.then(snapshot => {
end = start
start = snapshot.docs[snapshot.docs.length - 1]
const listener = collectionRef
.orderBy('createTimestamp')
.startAt(start)
.endBefore(end)
.onSnapshot(messages => {
messages.forEach(message => {
const mappedMessage = this.convertObjectTimestampPropertiesToDate(
{
id: message.id,
...message.data()
}
)
store.commit('chats/addMessage', mappedMessage)
})
})
store.commit('chats/setObserver', listener)
})
}
我的Vuex变异将消息添加到阵列:
addMessage: (state, message) => {
const exists = state.messages.find(m => {
return m.id === message.id
})
if (!exists) {
state.messages.push(message)
}
},
以下是可视化情况:
这是运行getMoreMessages()
后时间戳的控制台日志:
TEXT 9 TIMESTAMP Wed Sep 25 2019 16:14:09 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 10 TIMESTAMP Wed Sep 25 2019 16:14:10 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 11 TIMESTAMP Wed Sep 25 2019 16:14:11 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 12 TIMESTAMP Wed Sep 25 2019 16:14:12 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 13 TIMESTAMP Wed Sep 25 2019 16:14:13 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 14 TIMESTAMP Wed Sep 25 2019 16:14:14 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 15 TIMESTAMP Wed Sep 25 2019 16:14:15 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 16 TIMESTAMP Wed Sep 25 2019 16:14:16 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 17 TIMESTAMP Wed Sep 25 2019 16:14:18 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 18 TIMESTAMP Wed Sep 25 2019 16:14:19 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 1 TIMESTAMP Wed Sep 25 2019 16:13:24 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 2 TIMESTAMP Wed Sep 25 2019 16:13:43 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 3 TIMESTAMP Wed Sep 25 2019 16:13:50 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 4 TIMESTAMP Wed Sep 25 2019 16:14:05 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 5 TIMESTAMP Wed Sep 25 2019 16:14:06 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 6 TIMESTAMP Wed Sep 25 2019 16:14:07 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 7 TIMESTAMP Wed Sep 25 2019 16:14:08 GMT+0300 (Eastern European Summer Time)
chats.mutations.js?7021:29 TEXT 8 TIMESTAMP Wed Sep 25 2019 16:14:08 GMT+0300 (Eastern European Summer Time)
我不明白我在做什么错。看起来查询工作正常,但附加逻辑失败。我尝试执行unshift()
而不是.push()
并在前端按时间戳排序,但顺序也有误。任何帮助深表感谢!
答案 0 :(得分:0)
您是否在订单中缺少'desc'
?默认情况下,Firestore将使用asc
,但在您的第一个电话中,您看到的是您指定的desc
。