Ceramic Append Collection

This guide describes how to create, update, and query an Append Collection based on CIP-85.

Installation

npm install @cbj/ceramic-append-collection

Basic Use

import { AppendCollection } from '@cbj/ceramic-append-collection'

const collection = await AppendCollection.create(ceramic, { sliceMaxItems })
/* or */
const collection = await AppendCollection.load(ceramic, streamId)
const streamId = collection.id.toString()

const cursor = await collection.insert({ foo: 'bar' })
const cursor2 = await collection.insert({ foo: 'baz' })
const item1 = await collection.getItem(cursor)
const item2 = await collection.getItem(cursor2)
console.log(item1.value) // { foo: 'bar' }
console.log(item2.value) // { foo: 'baz' }
	
let firstItems = await collection.getFirstN(1) 
console.log(firstItems) // [ { foo: 'bar' } ]
firstItems = await collection.getFirstN(2)
console.log(firstItems) // [ { foo: 'baz' }, { foo: 'baz' } ]
let lastItems = await collection.getLastN(1) 
console.log(lastItems) // [ { foo: 'baz' } ]
lastItems = await collection.getLastN(2)
console.log(lastItems) // [ { foo: 'baz' }, { foo: 'bar' } ]

await collection.remove(item1.cursor)
firstItems = await collection.getFirstN(2)
console.log(firstItems) // [ { foo: 'baz' } ]
await collection.remove(item2.cursor)
firstItems = await collection.getFirstN(2)
console.log(firstItems) // []

Query a Collection

getFirstN(N: number, fromCursor?: Cursor | null): Promise<Item[]>;

getLastN(N: number, fromCursor?: Cursor | null): Promise<Item[]>;

getItem(cursor: Cursor): Promise<Item | null>;

getHeadCursor(): Promise<Cursor | null>;

getTailCursor(): Promise<Cursor | null>;

getNextCursor(cursor: Cursor): Promise<Cursor | null>;

getPreviousCursor(cursor: Cursor): Promise<Cursor | null>;

getSlicesCount(): Promise<number>;