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Collections

What is a Collection​

An collection is a set of feeds that are shared among peers. A feed is an append-only log of records. Each feed is only writable from a single device. A record is a unit of data. Each record has a type and a value and is identified by an ID.

Add or open collections​

To add a new collection to the workspace you call the createCollection() method, and to open an existing collection use the openCollection() method.

Each collection is identified by a local collectionName, which can be any string. To open an existing remote collection, pass in that collection's key as an hex-encoded string (that means: if the collectionName is a valid hex-encoded collection key, than Sonar will try to open it as a remote collection. Otherwise a new collection is created.)

async function getCollection(workspace: Workspace, collectionName: string): Promise<Collection> {
  try {
    collection = await workspace.openCollection(collectionName)
  } catch (err: any) {
    collection = await workspace.createCollection(collectionName)
  }
  return collection
}

Collection info​

Once a collection is opened, various informational fields are available on collection.info:

  • info.key: The collection's primary key, as hex-encoded string. Pass this to other peers if you want to share read access to your collection.
  • info.feeds: An array of the feeds that are part of this collection.
  • info.peers: An array of peers the collection is connected to.

Use await collection.updateInfo() to ensure that you have the most up-to-date collection information, if needed.