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{"version":3,"file":"sync.cjs","sources":["../sync.js"],"sourcesContent":["/**\n * @module sync-protocol\n */\n\nimport * as encoding from 'lib0/encoding'\nimport * as decoding from 'lib0/decoding'\nimport * as Y from 'yjs'\n\n/**\n * @typedef {Map<number, number>} StateMap\n */\n\n/**\n * Core Yjs defines two message types:\n * • YjsSyncStep1: Includes the State Set of the sending client. When received, the client should reply with YjsSyncStep2.\n * • YjsSyncStep2: Includes all missing structs and the complete delete set. When received, the client is assured that it\n * received all information from the remote client.\n *\n * In a peer-to-peer network, you may want to introduce a SyncDone message type. Both parties should initiate the connection\n * with SyncStep1. When a client received SyncStep2, it should reply with SyncDone. When the local client received both\n * SyncStep2 and SyncDone, it is assured that it is synced to the remote client.\n *\n * In a client-server model, you want to handle this differently: The client should initiate the connection with SyncStep1.\n * When the server receives SyncStep1, it should reply with SyncStep2 immediately followed by SyncStep1. The client replies\n * with SyncStep2 when it receives SyncStep1. Optionally the server may send a SyncDone after it received SyncStep2, so the\n * client knows that the sync is finished. There are two reasons for this more elaborated sync model: 1. This protocol can\n * easily be implemented on top of http and websockets. 2. The server should only reply to requests, and not initiate them.\n * Therefore it is necessary that the client initiates the sync.\n *\n * Construction of a message:\n * [messageType : varUint, message definition..]\n *\n * Note: A message does not include information about the room name. This must to be handled by the upper layer protocol!\n *\n * stringify[messageType] stringifies a message definition (messageType is already read from the bufffer)\n */\n\nexport const messageYjsSyncStep1 = 0\nexport const messageYjsSyncStep2 = 1\nexport const messageYjsUpdate = 2\n\n/**\n * Create a sync step 1 message based on the state of the current shared document.\n *\n * @param {encoding.Encoder} encoder\n * @param {Y.Doc} doc\n */\nexport const writeSyncStep1 = (encoder, doc) => {\n encoding.writeVarUint(encoder, messageYjsSyncStep1)\n const sv = Y.encodeStateVector(doc)\n encoding.writeVarUint8Array(encoder, sv)\n}\n\n/**\n * @param {encoding.Encoder} encoder\n * @param {Y.Doc} doc\n * @param {Uint8Array} [encodedStateVector]\n */\nexport const writeSyncStep2 = (encoder, doc, encodedStateVector) => {\n encoding.writeVarUint(encoder, messageYjsSyncStep2)\n encoding.writeVarUint8Array(encoder, Y.encodeStateAsUpdate(doc, encodedStateVector))\n}\n\n/**\n * Read SyncStep1 message and reply with SyncStep2.\n *\n * @param {decoding.Decoder} decoder The reply to the received message\n * @param {encoding.Encoder} encoder The received message\n * @param {Y.Doc} doc\n */\nexport const readSyncStep1 = (decoder, encoder, doc) =>\n writeSyncStep2(encoder, doc, decoding.readVarUint8Array(decoder))\n\n/**\n * Read and apply Structs and then DeleteStore to a y instance.\n *\n * @param {decoding.Decoder} decoder\n * @param {Y.Doc} doc\n * @param {any} transactionOrigin\n */\nexport const readSyncStep2 = (decoder, doc, transactionOrigin) => {\n try {\n Y.applyUpdate(doc, decoding.readVarUint8Array(decoder), transactionOrigin)\n } catch (error) {\n // This catches errors that are thrown by event handlers\n console.error('Caught error while handling a Yjs update', error)\n }\n}\n\n/**\n * @param {encoding.Encoder} encoder\n * @param {Uint8Array} update\n */\nexport const writeUpdate = (encoder, update) => {\n encoding.writeVarUint(encoder, messageYjsUpdate)\n encoding.writeVarUint8Array(encoder, update)\n}\n\n/**\n * Read and apply Structs and then DeleteStore to a y instance.\n *\n * @param {decoding.Decoder} decoder\n * @param {Y.Doc} doc\n * @param {any} transactionOrigin\n */\nexport const readUpdate = readSyncStep2\n\n/**\
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