Firebase Database Pagination
Allows pagination for the Firebase RTDB.
Usage
All the normal methods return an array of DataSnapshots.
Keys
To paginate over all the keys of a node you can use:
const pagination = require('firebase-database-pagination')
const admin = require('firebase-admin').initializeApp()
const children = await pagination.key(admin.database().ref('node'), 10)This will fetch all children of node in batches of 10.
Value
To paginate over keys order by the nodes value you can use:
const pagination = require('firebase-database-pagination')
const admin = require('firebase-admin').initializeApp()
const children = await pagination.value(admin.database().ref('node'), 10)Child
To paginate over all the keys of a node order by a childs key you can use:
const pagination = require('firebase-database-pagination')
const admin = require('firebase-admin').initializeApp()
const children = await pagination.child(admin.database().ref('node'), 'childKey', 10)Transform parameter
The .key, .value and .child methods have a .transformed function property which allows each result to be converted to something else if needed.
The transformer parameter can return a value or a promised value.
const pagination = require('firebase-database-pagination')
const admin = require('firebase-admin').initializeApp()
const values = await pagination.key.transformed(admin.database().ref('node'), 10, nodeChildSnapshot => {
return { key: nodeChildSnapshot.key, value: nodeChildSnapshot.child('count') }
})
// values is an array of { key, count }
const values = await pagination.key.transformed(admin.database().ref('node'), 10, async nodeChildSnapshot => {
return await admin.database().ref('other').child(nodeChildSnapshot.key)
})
// values is an array of DataSnaphots pointing at /other/<nodeChildKey>Limiting the query
All of the methods except a parameter to return a subset of values.
const pagination = require('firebase-database-pagination')
const admin = require('firebase-admin').initializeApp()
// Return all keys where the value is equal to 10
await pagination.value(admin.database().ref('node'), 10, { equalTo: 10 })
// Return all keys where the value is greater then or equal to 10
await pagination.value(admin.database().ref('node'), 10, { startAt: 10 })
// Return all keys where the value is less then or equal to 20
await pagination.value(admin.database().ref('node'), 10, { endAt: 20 })
// Return all keys where the value is greater then or equal to 15 AND less than or equal to 25 (i.e. in the interval [15, 25])
await pagination.value(admin.database().ref('node'), 10, { startAt: 15, endAt: 25 })