I've encountered a similar issue with pagination before. The documentation provided is lacking in detail, specifically when it comes to navigating back to the previous page. It can be quite frustrating.
Below is my approach to implementing a simple pagination solution. Assuming that VueFire, Firebase, and BootstrapVue have already been set up, let's dive into the code.
Here's what no one tells you to do differently:
- Utilize programmatic binding in
VueFire instead of declarative binding (refer to this link)
- To retrieve the first visible item in
firebase, use documentSnapshots.docs[0]
<template>
<div>
<p>{{countries}}</p>
<b-button-group size="lg" class="mx-2">
<b-button :disabled="prev_btn" @click="previous" >«</b-button>
<b-button :disabled="next_btn" @click="next">»</b-button>
</b-button-group>
</div>
</template>
<script>
import firebase from 'firebase/app'
import 'firebase/auth'
import { db } from '../main'
export default {
name: 'Countries',
data () {
return {
countries: [],
limit: 2,
lastVisible: '',
firstVisible: '',
next_btn: false,
prev_btn: true
}
},
methods: {
next () {
if (!this.next_btn) {
// bind data with countries
this.$bind('countries', db.collection('Countries').orderBy('createdAt').startAfter(this.lastVisible).limit(this.limit))
// set last and first visible items
db.collection('Countries').orderBy('createdAt').startAfter(this.lastVisible).limit(this.limit).get().then(documentSnapshots => {
this.lastVisible = documentSnapshots.docs[documentSnapshots.docs.length - 1]
this.firstVisible = documentSnapshots.docs[0]
}).then(() => {
// Peep on the next next query to see if it gives zero
db.collection('Countries').orderBy('createdAt').startAfter(this.lastVisible).limit(this.limit).get()
.then(snap => {
if (snap.size === 0) {
//disable button if the next peeped result gets zero
this.next_btn = true
// enable previous button
this.prev_btn = false
} else {
// enable next button if peeped result is not zero
this.next_btn = false
// enable previous button
this.prev_btn = false
}
})
})
}
},
previous () {
// Ensure previous is not zero
db.collection('Countries').orderBy('createdAt').endBefore(this.firstVisible).limitToLast(this.limit).get().then(snap => { return snap.size })
.then(size => {
//confirm is not zero here
if (size !== 0) {
//bind the previous to countries
this.$bind('countries', db.collection('Countries').orderBy('createdAt').endBefore(this.firstVisible).limitToLast(this.limit))
// Set last and first visible
db.collection('Countries').orderBy('createdAt').endBefore(this.firstVisible).limitToLast(this.limit).get().then(documentSnapshots => {
this.lastVisible = documentSnapshots.docs[documentSnapshots.docs.length - 1]
this.firstVisible = documentSnapshots.docs[0]
}).then(() => {
// peep the next previous query
db.collection('Countries').orderBy('createdAt').endBefore(this.firstVisible).limitToLast(this.limit).get()
.then(snap => {
if (snap.size === 0) {
//if next peeped previous button gets 0 disable
this.prev_btn = true
this.next_btn = false
} else {
//if next peeped result is does not get 0 enable buttons
this.prev_btn = false
this.next_btn = false
}
})
})
}
})
}
},
mounted () {
// run first query and bind data
this.$bind('countries', db.collection('Countries').orderBy('createdAt').limit(this.limit))
// set last and first Visible
db.collection('Countries').orderBy('createdAt').limit(this.limit).get().then(documentSnapshots => {
this.lastVisible = documentSnapshots.docs[documentSnapshots.docs.length - 1]
this.firstVisible = documentSnapshots.docs[0]
}).then(() => {
// peep to check if next should be on or off
db.collection('Countries').orderBy('createdAt').startAfter(this.lastVisible).limit(this.limit).get()
.then(snap => {
if (snap.size === 0) {
this.next_btn = true
}
})
})
}
}
</script>