feat: make it possible to customize the logger in cojson

.changeset/sixty-lizards-relax.md

@@ -0,0 +1,8 @@
+---
+"cojson-storage-sqlite": patch
+"cojson-transport-ws": patch
+"cojson-storage": patch
+"cojson": patch
+---
+
+Wrap all the console logs with a logger class to make possible to customize the logger

packages/cojson-storage-sqlite/src/sqliteClient.ts

@@ -1,5 +1,10 @@
 import { Database as DatabaseT } from "better-sqlite3";
-import { CojsonInternalTypes, OutgoingSyncQueue, SessionID } from "cojson";
+import {
+  CojsonInternalTypes,
+  OutgoingSyncQueue,
+  SessionID,
+  logger,
+} from "cojson";
 import RawCoID = CojsonInternalTypes.RawCoID;
 import Signature = CojsonInternalTypes.Signature;
 import Transaction = CojsonInternalTypes.Transaction;
@@ -48,7 +53,7 @@ export class SQLiteClient implements DBClientInterface {
         header: parsedHeader,
       };
     } catch (e) {
-      console.warn(coValueId, "Invalid JSON in header", e, coValueRow?.header);
+      logger.warn(coValueId, "Invalid JSON in header", e, coValueRow?.header);
       return;
     }
   }
@@ -75,7 +80,7 @@ export class SQLiteClient implements DBClientInterface {
         tx: JSON.parse(transactionRow.tx) as Transaction,
       }));
     } catch (e) {
-      console.warn("Invalid JSON in transaction", e);
+      logger.warn("Invalid JSON in transaction", e);
       return [];
     }
   }

packages/cojson-storage-sqlite/src/sqliteNode.ts

@@ -4,6 +4,7 @@ import {
   OutgoingSyncQueue,
   Peer,
   cojsonInternals,
+  logger,
 } from "cojson";
 import { SyncManager, TransactionRow } from "cojson-storage";
 import { SQLiteClient } from "./sqliteClient.js";
@@ -40,25 +41,23 @@ export class SQLiteNode {
             await new Promise((resolve) => setTimeout(resolve, 0));
           }
         } catch (e) {
-          console.error(
-            new Error(
-              `Error reading from localNode, handling msg\n\n${JSON.stringify(
-                msg,
-                (k, v) =>
-                  k === "changes" || k === "encryptedChanges"
-                    ? v.slice(0, 20) + "..."
-                    : v,
-              )}`,
-              { cause: e },
-            ),
+          logger.error(
+            `Error reading from localNode, handling msg\n\n${JSON.stringify(
+              msg,
+              (k, v) =>
+                k === "changes" || k === "encryptedChanges"
+                  ? v.slice(0, 20) + "..."
+                  : v,
+            )}`,
+            e,
           );
         }
       }
-    };
 
-    processMessages().catch((e) =>
-      console.error("Error in processMessages in sqlite", e),
-    );
+      processMessages().catch((e) =>
+        logger.error("Error in processMessages in sqlite", e),
+      );
+    };
   }
 
   static async asPeer({
@@ -97,10 +96,7 @@ export class SQLiteNode {
       db.pragma("user_version") as [{ user_version: number }]
     )[0].user_version as number;
 
-    console.log("DB version", oldVersion);
-
     if (oldVersion === 0) {
-      console.log("Migration 0 -> 1: Basic schema");
       db.prepare(
         `CREATE TABLE IF NOT EXISTS transactions (
                     ses INTEGER,
@@ -138,15 +134,10 @@ export class SQLiteNode {
       ).run();
 
       db.pragma("user_version = 1");
-      console.log("Migration 0 -> 1: Basic schema - done");
     }
 
     if (oldVersion <= 1) {
       // fix embarrassing off-by-one error for transaction indices
-      console.log(
-        "Migration 1 -> 2: Fix off-by-one error for transaction indices",
-      );
-
       const txs = db
         .prepare(`SELECT * FROM transactions`)
         .all() as TransactionRow[];
@@ -163,14 +154,9 @@ export class SQLiteNode {
       }
 
       db.pragma("user_version = 2");
-      console.log(
-        "Migration 1 -> 2: Fix off-by-one error for transaction indices - done",
-      );
     }
 
     if (oldVersion <= 2) {
-      console.log("Migration 2 -> 3: Add signatureAfter");
-
       db.prepare(
         `CREATE TABLE IF NOT EXISTS signatureAfter (
                     ses INTEGER,
@@ -185,7 +171,6 @@ export class SQLiteNode {
       ).run();
 
       db.pragma("user_version = 3");
-      console.log("Migration 2 -> 3: Add signatureAfter - done!!");
     }
 
     return new SQLiteNode(db, fromLocalNode, toLocalNode);

packages/cojson-storage/src/syncManager.ts

@@ -6,6 +6,7 @@ import {
   SyncMessage,
   cojsonInternals,
   emptyKnownState,
+  logger,
 } from "cojson";
 import { collectNewTxs, getDependedOnCoValues } from "./syncUtils.js";
 import { DBClientInterface, StoredSessionRow } from "./types.js";
@@ -314,7 +315,7 @@ export class SyncManager {
     return this.toLocalNode
       .push(msg)
       .catch((e) =>
-        console.error(`Error sending ${msg.action} state, id ${msg.id}`, e),
+        logger.error(`Error sending ${msg.action} state, id ${msg.id}`, e),
       );
   }
 }

packages/cojson-transport-ws/src/index.ts

@@ -4,6 +4,7 @@ import {
   PingTimeoutError,
   SyncMessage,
   cojsonInternals,
+  logger,
 } from "cojson";
 import { BatchedOutgoingMessages } from "./BatchedOutgoingMessages.js";
 import { deserializeMessages } from "./serialization.js";
@@ -136,7 +137,7 @@ export function createWebSocketPeer({
   function handleClose() {
     incoming
       .push("Disconnected")
-      .catch((e) => console.error("Error while pushing disconnect msg", e));
+      .catch((e) => logger.error("Error while pushing disconnect msg", e));
     emitClosedEvent();
   }
 
@@ -145,7 +146,7 @@ export function createWebSocketPeer({
   const pingTimeout = createPingTimeoutListener(expectPings, () => {
     incoming
       .push("PingTimeout")
-      .catch((e) => console.error("Error while pushing ping timeout", e));
+      .catch((e) => logger.error("Error while pushing ping timeout", e));
     emitClosedEvent();
   });
 
@@ -156,14 +157,13 @@ export function createWebSocketPeer({
 
   function handleIncomingMsg(event: { data: unknown }) {
     if (event.data === "") {
-      console.log("client", id, "sent empty message");
       return;
     }
 
     const result = deserializeMessages(event.data);
 
     if (!result.ok) {
-      console.error(
+      logger.warn(
         "Error while deserializing messages",
         event.data,
         result.error,
@@ -184,7 +184,7 @@ export function createWebSocketPeer({
       if (msg && "action" in msg) {
         incoming
           .push(msg)
-          .catch((e) => console.error("Error while pushing incoming msg", e));
+          .catch((e) => logger.error("Error while pushing incoming msg", e));
       }
     }
   }
@@ -197,7 +197,6 @@ export function createWebSocketPeer({
     outgoing: {
       push: outgoingMessages.sendMessage,
       close() {
-        console.log("Trying to close", id, websocket.readyState);
         outgoingMessages.close();
 
         websocket.removeEventListener("message", handleIncomingMsg);

packages/cojson-transport-ws/src/serialization.ts

@@ -1,4 +1,4 @@
-import { SyncMessage } from "cojson";
+import { SyncMessage, logger } from "cojson";
 import { PingMsg } from "./types.js";
 
 export function addMessageToBacklog(backlog: string, message: SyncMessage) {
@@ -24,7 +24,7 @@ export function deserializeMessages(messages: unknown) {
         | PingMsg[],
     } as const;
   } catch (e) {
-    console.error("Error while deserializing messages", e);
+    logger.error("Error while deserializing messages", e);
     return {
       ok: false,
       error: e,

packages/cojson/src/PeerState.ts

@@ -5,6 +5,7 @@ import {
 } from "./PriorityBasedMessageQueue.js";
 import { TryAddTransactionsError } from "./coValueCore.js";
 import { RawCoID } from "./ids.js";
+import { logger } from "./logger.js";
 import { CO_VALUE_PRIORITY } from "./priority.js";
 import { Peer, SyncMessage } from "./sync.js";
 
@@ -137,7 +138,7 @@ export class PeerState {
   }
 
   gracefulShutdown() {
-    console.debug("Gracefully closing", this.id);
+    logger.debug("Gracefully closing", this.id);
     this.closeQueue();
     this.peer.outgoing.close();
     this.closed = true;

packages/cojson/src/base64url.ts

@@ -43,12 +43,7 @@ export function bytesToBase64url(bytes: Uint8Array) {
   let base64 = decoder.decode(new Uint8Array(encoded.buffer, 0, n));
   if (k === 1) base64 += "==";
   if (k === 2) base64 += "=";
-  // const after = performance.now();
-  // console.log(
-  //     "bytesToBase64url bandwidth in MB/s for length",
-  //     (1000 * bytes.length / (after - before)) / (1024 * 1024),
-  //     bytes.length
-  // );
+
   return base64;
 }
 

packages/cojson/src/coValueCore.ts

@@ -24,6 +24,7 @@ import {
 import { Stringified, parseJSON, stableStringify } from "./jsonStringify.js";
 import { JsonObject, JsonValue } from "./jsonValue.js";
 import { LocalNode, ResolveAccountAgentError } from "./localNode.js";
+import { logger } from "./logger.js";
 import {
   PermissionsDef as RulesetDef,
   determineValidTransactions,
@@ -209,16 +210,10 @@ export class CoValueCore {
       .andThen((agent) => {
         const signerID = this.crypto.getAgentSignerID(agent);
 
-        // const beforeHash = performance.now();
         const { expectedNewHash, newStreamingHash } = this.expectedNewHashAfter(
           sessionID,
           newTransactions,
         );
-        // const afterHash = performance.now();
-        // console.log(
-        //     "Hashing took",
-        //     afterHash - beforeHash
-        // );
 
         if (givenExpectedNewHash && givenExpectedNewHash !== expectedNewHash) {
           return err({
@@ -391,7 +386,6 @@ export class CoValueCore {
       streamingHash.update(transaction);
       const after = performance.now();
       if (after - before > 1) {
-        // console.log("Hashing blocked for", after - before);
         await new Promise((resolve) => setTimeout(resolve, 0));
         before = performance.now();
       }
@@ -540,7 +534,7 @@ export class CoValueCore {
       }
 
       if (!decryptedChanges) {
-        console.error("Failed to decrypt transaction despite having key");
+        logger.error("Failed to decrypt transaction despite having key");
         continue;
       }
 
@@ -685,7 +679,7 @@ export class CoValueCore {
           if (secret) {
             return secret as KeySecret;
           } else {
-            console.error(
+            logger.warn(
               `Encrypting ${encryptingKeyID} key didn't decrypt ${keyID}`,
             );
           }
@@ -725,7 +719,7 @@ export class CoValueCore {
               if (secret) {
                 return secret as KeySecret;
               } else {
-                console.error(
+                logger.warn(
                   `Encrypting parent ${parentKey.id} key didn't decrypt ${keyID}`,
                 );
               }

packages/cojson/src/coValueState.ts

@@ -1,6 +1,7 @@
 import { PeerState } from "./PeerState.js";
 import { CoValueCore } from "./coValueCore.js";
 import { RawCoID } from "./ids.js";
+import { logger } from "./logger.js";
 import { PeerID } from "./sync.js";
 
 export const CO_VALUE_LOADING_MAX_RETRIES = 5;
@@ -282,7 +283,7 @@ async function loadCoValueFromPeers(
           ...coValueEntry.state.coValue.knownState(),
         })
         .catch((err) => {
-          console.error(`Failed to push load message to peer ${peer.id}`, err);
+          logger.warn(`Failed to push load message to peer ${peer.id}`, err);
         });
     } else {
       /**
@@ -296,14 +297,14 @@ async function loadCoValueFromPeers(
           sessions: {},
         })
         .catch((err) => {
-          console.error(`Failed to push load message to peer ${peer.id}`, err);
+          logger.warn(`Failed to push load message to peer ${peer.id}`, err);
         });
     }
 
     if (coValueEntry.state.type === "loading") {
       const timeout = setTimeout(() => {
         if (coValueEntry.state.type === "loading") {
-          console.error("Failed to load coValue from peer", peer.id);
+          logger.warn("Failed to load coValue from peer", peer.id);
           coValueEntry.dispatch({
             type: "not-found-in-peer",
             peerId: peer.id,
@@ -356,7 +357,7 @@ function sleep(ms: number) {
 function getPeersWithoutErrors(peers: PeerState[], coValueId: RawCoID) {
   return peers.filter((p) => {
     if (p.erroredCoValues.has(coValueId)) {
-      console.error(
+      logger.warn(
         `Skipping load on errored coValue ${coValueId} from peer ${p.id}`,
       );
       return false;

packages/cojson/src/coValues/account.ts

@@ -16,6 +16,7 @@ import {
 import { AgentID } from "../ids.js";
 import { JsonObject } from "../jsonValue.js";
 import { LocalNode } from "../localNode.js";
+import { logger } from "../logger.js";
 import type { AccountRole } from "../permissions.js";
 import { RawCoMap } from "./coMap.js";
 import { InviteSecret, RawGroup } from "./group.js";
@@ -59,7 +60,7 @@ export class RawAccount<
       );
 
     if (agents.length !== 1) {
-      console.warn("Account has " + agents.length + " agents", this.id);
+      logger.warn("Account has " + agents.length + " agents", this.id);
     }
 
     this._cachedCurrentAgentID = agents[0];

packages/cojson/src/coValues/coList.ts

@@ -133,10 +133,6 @@ export class RawCoListView<
                   change.before.txIndex
                 ]?.[change.before.changeIdx];
               if (!beforeEntry) {
-                // console.error(
-                //     "Insertion before missing op " +
-                //         change.before
-                // );
                 continue;
               }
               beforeEntry.predecessors.splice(0, 0, {
@@ -156,9 +152,6 @@ export class RawCoListView<
                   change.after.txIndex
                 ]?.[change.after.changeIdx];
               if (!afterEntry) {
-                // console.error(
-                //     "Insertion after missing op " + change.after
-                // );
                 continue;
               }
               afterEntry.successors.push({

packages/cojson/src/coValues/coStream.ts

@@ -3,6 +3,7 @@ import { CoID, RawCoValue } from "../coValue.js";
 import { CoValueCore } from "../coValueCore.js";
 import { AgentID, SessionID, TransactionID } from "../ids.js";
 import { JsonObject, JsonValue } from "../jsonValue.js";
+import { logger } from "../logger.js";
 import { CoValueKnownState } from "../sync.js";
 import { accountOrAgentIDfromSessionID } from "../typeUtils/accountOrAgentIDfromSessionID.js";
 import { isAccountID } from "../typeUtils/isAccountID.js";
@@ -309,7 +310,7 @@ export class RawBinaryCoStreamView<
     const start = items[0];
 
     if (start?.type !== "start") {
-      console.error("Invalid binary stream start", start);
+      logger.error("Invalid binary stream start", start);
       return;
     }
 
@@ -328,7 +329,7 @@ export class RawBinaryCoStreamView<
       }
 
       if (item.type !== "chunk") {
-        console.error("Invalid binary stream chunk", item);
+        logger.error("Invalid binary stream chunk", item);
         return undefined;
       }
 
@@ -382,7 +383,6 @@ export class RawBinaryCoStream<
     chunk: Uint8Array,
     privacy: "private" | "trusting" = "private",
   ): void {
-    // const before = performance.now();
     this.push(
       {
         type: "chunk",
@@ -391,11 +391,6 @@ export class RawBinaryCoStream<
       privacy,
       false,
     );
-    // const after = performance.now();
-    // console.log(
-    //     "pushBinaryStreamChunk bandwidth in MB/s",
-    //     (1000 * chunk.length) / (after - before) / (1024 * 1024)
-    // );
   }
 
   endBinaryStream(privacy: "private" | "trusting" = "private") {

packages/cojson/src/coValues/group.ts

@@ -13,6 +13,7 @@ import {
   isParentGroupReference,
 } from "../ids.js";
 import { JsonObject } from "../jsonValue.js";
+import { logger } from "../logger.js";
 import { AccountRole, Role } from "../permissions.js";
 import { expectGroup } from "../typeUtils/expectGroup.js";
 import {
@@ -153,7 +154,7 @@ export class RawGroup<
         child.state.type === "unavailable"
       ) {
         child.loadFromPeers(peers).catch(() => {
-          console.error(`Failed to load child group ${id}`);
+          logger.error(`Failed to load child group ${id}`);
         });
       }
 
@@ -321,7 +322,7 @@ export class RawGroup<
         const secret = this.core.getReadKey(keyID);
 
         if (!secret) {
-          console.error("Can't find key", keyID);
+          logger.error("Can't find key", keyID);
           continue;
         }
 

packages/cojson/src/crypto/PureJSCrypto.ts

@@ -7,6 +7,7 @@ import { base64URLtoBytes, bytesToBase64url } from "../base64url.js";
 import { RawCoID, TransactionID } from "../ids.js";
 import { Stringified, stableStringify } from "../jsonStringify.js";
 import { JsonValue } from "../jsonValue.js";
+import { logger } from "../logger.js";
 import {
   CryptoProvider,
   Encrypted,
@@ -192,7 +193,7 @@ export class PureJSCrypto extends CryptoProvider<Blake3State> {
     try {
       return JSON.parse(textDecoder.decode(plaintext));
     } catch (e) {
-      console.error("Failed to decrypt/parse sealed message", e);
+      logger.error("Failed to decrypt/parse sealed message", e);
       return undefined;
     }
   }

packages/cojson/src/crypto/WasmCrypto.ts

@@ -15,6 +15,7 @@ import { base64URLtoBytes, bytesToBase64url } from "../base64url.js";
 import { RawCoID, TransactionID } from "../ids.js";
 import { Stringified, stableStringify } from "../jsonStringify.js";
 import { JsonValue } from "../jsonValue.js";
+import { logger } from "../logger.js";
 import {
   CryptoProvider,
   Encrypted,
@@ -240,7 +241,7 @@ export class WasmCrypto extends CryptoProvider<Uint8Array> {
     try {
       return JSON.parse(textDecoder.decode(plaintext));
     } catch (e) {
-      console.error("Failed to decrypt/parse sealed message", e);
+      logger.error("Failed to decrypt/parse sealed message", e);
       return undefined;
     }
   }

packages/cojson/src/crypto/crypto.ts

@@ -4,6 +4,7 @@ import { AgentID, RawCoID, TransactionID } from "../ids.js";
 import { SessionID } from "../ids.js";
 import { Stringified, parseJSON, stableStringify } from "../jsonStringify.js";
 import { JsonValue } from "../jsonValue.js";
+import { logger } from "../logger.js";
 
 export type SignerSecret = `signerSecret_z${string}`;
 export type SignerID = `signer_z${string}`;
@@ -159,7 +160,7 @@ export abstract class CryptoProvider<Blake3State = any> {
     try {
       return parseJSON(this.decryptRaw(encrypted, keySecret, nOnceMaterial));
     } catch (e) {
-      console.error("Decryption error", e);
+      logger.error("Decryption error", e);
       return undefined;
     }
   }
@@ -305,10 +306,7 @@ export class StreamingHash {
 
   update(value: JsonValue): Uint8Array {
     const encoded = textEncoder.encode(stableStringify(value));
-    // const before = performance.now();
     this.state = this.crypto.blake3IncrementalUpdate(this.state, encoded);
-    // const after = performance.now();
-    // console.log(`Hashing throughput in MB/s`, 1000 * (encoded.length / (after - before)) / (1024 * 1024));
     return encoded;
   }
 

packages/cojson/src/exports.ts

@@ -74,6 +74,7 @@ import {
 
 type Value = JsonValue | AnyRawCoValue;
 
+import { logger } from "./logger.js";
 import { getPriorityFromHeader } from "./priority.js";
 import { FileSystem } from "./storage/FileSystem.js";
 import { BlockFilename, LSMStorage, WalFilename } from "./storage/index.js";
@@ -141,6 +142,7 @@ export {
   emptyKnownState,
   RawCoPlainText,
   stringifyOpID,
+  logger,
 };
 
 export type {

packages/cojson/src/localNode.ts

@@ -27,6 +27,7 @@ import {
 } from "./coValues/group.js";
 import { AgentSecret, CryptoProvider } from "./crypto/crypto.js";
 import { AgentID, RawCoID, SessionID, isAgentID } from "./ids.js";
+import { logger } from "./logger.js";
 import { Peer, PeerID, SyncManager } from "./sync.js";
 import { expectGroup } from "./typeUtils/expectGroup.js";
 
@@ -230,7 +231,7 @@ export class LocalNode {
 
       return node;
     } catch (e) {
-      console.error("Error withLoadedAccount", e);
+      logger.error("Error withLoadedAccount", e);
       throw e;
     }
   }
@@ -269,7 +270,7 @@ export class LocalNode {
         this.syncManager.getServerAndStoragePeers(skipLoadingFromPeer);
 
       await entry.loadFromPeers(peers).catch((e) => {
-        console.error("Error loading from peers", id, e);
+        logger.error("Error loading from peers", id, e);
       });
     }
 
@@ -311,8 +312,6 @@ export class LocalNode {
     let stopped = false;
     let unsubscribe!: () => void;
 
-    // console.log("Subscribing to " + id);
-
     this.load(id)
       .then((coValue) => {
         if (stopped) {
@@ -325,11 +324,10 @@ export class LocalNode {
         unsubscribe = coValue.subscribe(callback);
       })
       .catch((e) => {
-        console.error("Error subscribing to ", id, e);
+        logger.error("Error subscribing to ", id, e);
       });
 
     return () => {
-      console.log("Unsubscribing from " + id);
       stopped = true;
       unsubscribe?.();
     };
@@ -390,9 +388,7 @@ export class LocalNode {
       (existingRole === "reader" && inviteRole === "readerInvite") ||
       (existingRole && inviteRole === "writeOnlyInvite")
     ) {
-      console.debug(
-        "Not accepting invite that would replace or downgrade role",
-      );
+      logger.debug("Not accepting invite that would replace or downgrade role");
       return;
     }
 

packages/cojson/src/logger.ts

@@ -0,0 +1,78 @@
+export enum LogLevel {
+  DEBUG = 0,
+  INFO = 1,
+  WARN = 2,
+  ERROR = 3,
+  NONE = 4,
+}
+
+export interface LogSystem {
+  debug(message: string, ...args: any[]): void;
+  info(message: string, ...args: any[]): void;
+  warn(message: string, ...args: any[]): void;
+  error(message: string, ...args: any[]): void;
+}
+
+// Default console-based logging system
+export class ConsoleLogSystem implements LogSystem {
+  debug(message: string, ...args: any[]) {
+    console.debug(message, ...args);
+  }
+  info(message: string, ...args: any[]) {
+    console.info(message, ...args);
+  }
+  warn(message: string, ...args: any[]) {
+    console.warn(message, ...args);
+  }
+  error(message: string, ...args: any[]) {
+    console.error(message, ...args);
+  }
+}
+
+export class Logger {
+  private level: LogLevel;
+  private logSystem: LogSystem;
+
+  constructor(
+    level: LogLevel = LogLevel.INFO,
+    logSystem: LogSystem = new ConsoleLogSystem(),
+  ) {
+    this.level = level;
+    this.logSystem = logSystem;
+  }
+
+  setLevel(level: LogLevel) {
+    this.level = level;
+  }
+
+  setLogSystem(logSystem: LogSystem) {
+    this.logSystem = logSystem;
+  }
+
+  debug(message: string, ...args: any[]) {
+    if (this.level <= LogLevel.DEBUG) {
+      this.logSystem.debug(message, ...args);
+    }
+  }
+
+  info(message: string, ...args: any[]) {
+    if (this.level <= LogLevel.INFO) {
+      this.logSystem.info(message, ...args);
+    }
+  }
+
+  warn(message: string, ...args: any[]) {
+    if (this.level <= LogLevel.WARN) {
+      this.logSystem.warn(message, ...args);
+    }
+  }
+
+  error(message: string, ...args: any[]) {
+    if (this.level <= LogLevel.ERROR) {
+      this.logSystem.error(message, ...args);
+    }
+  }
+}
+
+// Create default logger instance
+export const logger = new Logger();

packages/cojson/src/permissions.ts

@@ -14,6 +14,7 @@ import {
 } from "./ids.js";
 import { parseJSON } from "./jsonStringify.js";
 import { JsonValue } from "./jsonValue.js";
+import { logger } from "./logger.js";
 import { accountOrAgentIDfromSessionID } from "./typeUtils/accountOrAgentIDfromSessionID.js";
 import { expectGroup } from "./typeUtils/expectGroup.js";
 
@@ -46,7 +47,7 @@ function logPermissionError(...args: unknown[]) {
     return;
   }
 
-  console.warn(...args);
+  logger.warn("Permission error", ...args);
 }
 
 export function determineValidTransactions(
@@ -204,7 +205,6 @@ function determineValidTransactionsForGroup(
   const writeKeys = new Set<string>();
 
   for (const { sessionID, txIndex, tx } of allTransactionsSorted) {
-    // console.log("before", { memberState, validTransactions });
     const transactor = accountOrAgentIDfromSessionID(sessionID);
 
     if (tx.privacy === "private") {
@@ -458,8 +458,6 @@ function determineValidTransactionsForGroup(
 
     memberState[affectedMember] = change.value;
     validTransactions.push({ txID: { sessionID, txIndex }, tx });
-
-    // console.log("after", { memberState, validTransactions });
   }
 
   return { validTransactions, memberState };
@@ -473,7 +471,7 @@ function agentInAccountOrMemberInGroup(
     return groupAtTime.currentAgentID().match(
       (agentID) => agentID,
       (e) => {
-        console.error(
+        logger.error(
           "Error while determining current agent ID in valid transactions",
           e,
         );

packages/cojson/src/storage/FileSystem.ts

@@ -87,26 +87,15 @@ export async function writeBlock<WH, RH, FS extends FileSystem<WH, RH>>(
   const headerBytes = textEncoder.encode(JSON.stringify(blockHeader));
   await fs.append(file, headerBytes);
 
-  // console.log(
-  //     "full file",
-  //     yield* $(
-  //         fs.read(file as unknown as RH, 0, offset + headerBytes.length),
-  //     ),
-  // );
-
   const filename: BlockFilename = `L${level}-${(blockNumber + "").padStart(
     3,
     "0",
   )}-${hash.digest().replace("hash_", "").slice(0, 15)}-H${
     headerBytes.length
   }.jsonl`;
-  // console.log("renaming to" + filename);
   await fs.closeAndRename(file, filename);
 
   return filename;
-
-  // console.log("Wrote block", filename, blockHeader);
-  // console.log("IDs in block", blockHeader.map(e => e.id));
 }
 
 export async function writeToWal<WH, RH, FS extends FileSystem<WH, RH>>(
@@ -120,6 +109,5 @@ export async function writeToWal<WH, RH, FS extends FileSystem<WH, RH>>(
     ...chunk,
   };
   const bytes = textEncoder.encode(JSON.stringify(walEntry) + "\n");
-  console.log("writing to WAL", handle, id, bytes.length);
   return fs.append(handle, bytes);
 }

packages/cojson/src/storage/index.ts

@@ -2,6 +2,7 @@ import { CoID, RawCoValue } from "../coValue.js";
 import { CoValueHeader, Transaction } from "../coValueCore.js";
 import { Signature } from "../crypto/crypto.js";
 import { RawCoID } from "../ids.js";
+import { logger } from "../logger.js";
 import { connectedPeers } from "../streamUtils.js";
 import {
   CoValueKnownState,
@@ -68,7 +69,6 @@ export class LSMStorage<WH, RH, FS extends FileSystem<WH, RH>> {
 
     const processMessages = async () => {
       for await (const msg of fromLocalNode) {
-        console.log("Storage msg start", nMsg);
         try {
           if (msg === "Disconnected" || msg === "PingTimeout") {
             throw new Error("Unexpected Disconnected message");
@@ -83,32 +83,29 @@ export class LSMStorage<WH, RH, FS extends FileSystem<WH, RH>> {
             await this.sendNewContent(msg.id, msg, undefined);
           }
         } catch (e) {
-          console.error(
-            new Error(
-              `Error reading from localNode, handling msg\n\n${JSON.stringify(
-                msg,
-                (k, v) =>
-                  k === "changes" || k === "encryptedChanges"
-                    ? v.slice(0, 20) + "..."
-                    : v,
-              )}`,
-              { cause: e },
-            ),
+          logger.error(
+            `Error reading from localNode, handling msg\n\n${JSON.stringify(
+              msg,
+              (k, v) =>
+                k === "changes" || k === "encryptedChanges"
+                  ? v.slice(0, 20) + "..."
+                  : v,
+            )}`,
+            e,
           );
         }
-        console.log("Storage msg end", nMsg);
         nMsg++;
       }
     };
 
     processMessages().catch((e) =>
-      console.error("Error in processMessages in storage", e),
+      logger.error("Error in processMessages in storage", e),
     );
 
     setTimeout(
       () =>
         this.compact().catch((e) => {
-          console.error("Error while compacting", e);
+          logger.error("Error while compacting", e);
         }),
       20000,
     );
@@ -134,7 +131,7 @@ export class LSMStorage<WH, RH, FS extends FileSystem<WH, RH>> {
           sessions: {},
           asDependencyOf,
         })
-        .catch((e) => console.error("Error while pushing known", e));
+        .catch((e) => logger.error("Error while pushing known", e));
 
       return;
     }
@@ -190,13 +187,13 @@ export class LSMStorage<WH, RH, FS extends FileSystem<WH, RH>> {
         ...ourKnown,
         asDependencyOf,
       })
-      .catch((e) => console.error("Error while pushing known", e));
+      .catch((e) => logger.error("Error while pushing known", e));
 
     for (const message of newContentMessages) {
       if (Object.keys(message.new).length === 0) continue;
       this.toLocalNode
         .push(message)
-        .catch((e) => console.error("Error while pushing new content", e));
+        .catch((e) => logger.error("Error while pushing new content", e));
     }
 
     this.coValues[id] = coValue;
@@ -232,20 +229,19 @@ export class LSMStorage<WH, RH, FS extends FileSystem<WH, RH>> {
 
     if (!coValue) {
       if (newContent.header) {
-        // console.log("Creating in WAL", newContent.id);
         await this.withWAL((wal) =>
           writeToWal(wal, this.fs, newContent.id, newContentAsChunk),
         );
 
         this.coValues[newContent.id] = newContentAsChunk;
       } else {
-        console.warn("Incontiguous incoming update for " + newContent.id);
+        logger.warn("Incontiguous incoming update for " + newContent.id);
         return;
       }
     } else {
       const merged = mergeChunks(coValue, newContentAsChunk);
       if (merged === "nonContigous") {
-        console.warn(
+        logger.warn(
           "Non-contigous new content for " + newContent.id,
           Object.entries(coValue.sessionEntries).map(([session, entries]) =>
             entries.map((entry) => ({
@@ -264,7 +260,6 @@ export class LSMStorage<WH, RH, FS extends FileSystem<WH, RH>> {
           ),
         );
       } else {
-        // console.log("Appending to WAL", newContent.id);
         await this.withWAL((wal) =>
           writeToWal(wal, this.fs, newContent.id, newContentAsChunk),
         );
@@ -301,8 +296,6 @@ export class LSMStorage<WH, RH, FS extends FileSystem<WH, RH>> {
 
       const { handle, size } = await this.getBlockHandle(blockFile, fs);
 
-      // console.log("Attempting to load", id, blockFile);
-
       if (!cachedHeader) {
         cachedHeader = {};
         const header = await readHeader(blockFile, handle, size, fs);
@@ -317,15 +310,13 @@ export class LSMStorage<WH, RH, FS extends FileSystem<WH, RH>> {
       }
       const headerEntry = cachedHeader[id];
 
-      // console.log("Header entry", id, headerEntry);
-
       if (headerEntry) {
         const nextChunk = await readChunk(handle, headerEntry, fs);
         if (result) {
           const merged = mergeChunks(result, nextChunk);
 
           if (merged === "nonContigous") {
-            console.warn(
+            logger.warn(
               "Non-contigous chunks while loading " + id,
               result,
               nextChunk,
@@ -354,7 +345,6 @@ export class LSMStorage<WH, RH, FS extends FileSystem<WH, RH>> {
 
     const coValues = new Map<RawCoID, CoValueChunk>();
 
-    console.log("Compacting WAL files", walFiles);
     if (walFiles.length === 0) return;
 
     const oldWal = this.currentWal;
@@ -385,7 +375,7 @@ export class LSMStorage<WH, RH, FS extends FileSystem<WH, RH>> {
         if (existingChunk) {
           const merged = mergeChunks(existingChunk, chunk);
           if (merged === "nonContigous") {
-            console.log(
+            logger.info(
               "Non-contigous chunks in " + chunk.id + ", " + fileName,
               existingChunk,
               chunk,
@@ -411,8 +401,6 @@ export class LSMStorage<WH, RH, FS extends FileSystem<WH, RH>> {
       return acc;
     }, 0);
 
-    console.log([...coValues.keys()], fileNames, highestBlockNumber);
-
     await writeBlock(coValues, MAX_N_LEVELS, highestBlockNumber + 1, this.fs);
 
     for (const walFile of walFiles) {
@@ -438,15 +426,11 @@ export class LSMStorage<WH, RH, FS extends FileSystem<WH, RH>> {
       blockFilesByLevelInOrder[level]!.push(blockFile);
     }
 
-    console.log(blockFilesByLevelInOrder);
-
     for (let level = MAX_N_LEVELS; level > 0; level--) {
       const nBlocksDesired = Math.pow(2, level);
       const blocksInLevel = blockFilesByLevelInOrder[level];
 
       if (blocksInLevel && blocksInLevel.length > nBlocksDesired) {
-        console.log("Compacting blocks in level", level, blocksInLevel);
-
         const coValues = new Map<RawCoID, CoValueChunk>();
 
         for (const blockFile of blocksInLevel) {
@@ -465,7 +449,7 @@ export class LSMStorage<WH, RH, FS extends FileSystem<WH, RH>> {
             if (existingChunk) {
               const merged = mergeChunks(existingChunk, chunk);
               if (merged === "nonContigous") {
-                console.log(
+                logger.info(
                   "Non-contigous chunks in " + entry.id + ", " + blockFile,
                   existingChunk,
                   chunk,
@@ -517,7 +501,7 @@ export class LSMStorage<WH, RH, FS extends FileSystem<WH, RH>> {
     setTimeout(
       () =>
         this.compact().catch((e) => {
-          console.error("Error while compacting", e);
+          logger.error("Error while compacting", e);
         }),
       5000,
     );

packages/cojson/src/sync.ts

@@ -6,6 +6,7 @@ import { CoValueCore } from "./coValueCore.js";
 import { Signature } from "./crypto/crypto.js";
 import { RawCoID, SessionID } from "./ids.js";
 import { LocalNode } from "./localNode.js";
+import { logger } from "./logger.js";
 import { CoValuePriority } from "./priority.js";
 
 export type CoValueKnownState = {
@@ -150,7 +151,7 @@ export class SyncManager {
 
   async handleSyncMessage(msg: SyncMessage, peer: PeerState) {
     if (peer.erroredCoValues.has(msg.id)) {
-      console.error(
+      logger.warn(
         `Skipping message ${msg.action} on errored coValue ${msg.id} from peer ${peer.id}`,
       );
       return;
@@ -182,7 +183,7 @@ export class SyncManager {
 
     if (entry.state.type !== "available") {
       entry.loadFromPeers([peer]).catch((e: unknown) => {
-        console.error("Error sending load", e);
+        logger.error("Error sending load", e);
       });
       return;
     }
@@ -199,7 +200,7 @@ export class SyncManager {
         action: "load",
         ...coValue.knownState(),
       }).catch((e: unknown) => {
-        console.error("Error sending load", e);
+        logger.error("Error sending load", e);
       });
     }
   }
@@ -229,7 +230,7 @@ export class SyncManager {
         asDependencyOf,
         ...coValue.knownState(),
       }).catch((e: unknown) => {
-        console.error("Error sending known state", e);
+        logger.error("Error sending known state", e);
       });
 
       peer.toldKnownState.add(id);
@@ -256,15 +257,8 @@ export class SyncManager {
       const sendPieces = async () => {
         let lastYield = performance.now();
         for (const [_i, piece] of newContentPieces.entries()) {
-          // console.log(
-          //     `${id} -> ${peer.id}: Sending content piece ${i + 1}/${
-          //         newContentPieces.length
-          //     } header: ${!!piece.header}`,
-          //     // Object.values(piece.new).map((s) => s.newTransactions)
-          // );
-
           this.trySendToPeer(peer, piece).catch((e: unknown) => {
-            console.error("Error sending content piece", e);
+            logger.error("Error sending content piece", e);
           });
 
           if (performance.now() - lastYield > 10) {
@@ -277,7 +271,7 @@ export class SyncManager {
       };
 
       sendPieces().catch((e) => {
-        console.error("Error sending new content piece, retrying", e);
+        logger.error("Error sending new content piece, retrying", e);
         peer.optimisticKnownStates.dispatch({
           type: "SET",
           id,
@@ -337,7 +331,7 @@ export class SyncManager {
           return;
         }
         if (msg === "PingTimeout") {
-          console.error("Ping timeout from peer", peer.id);
+          logger.error("Ping timeout from peer", peer.id);
           return;
         }
         try {
@@ -360,13 +354,13 @@ export class SyncManager {
     processMessages()
       .then(() => {
         if (peer.crashOnClose) {
-          console.error("Unexepcted close from peer", peer.id);
+          logger.warn("Unexepcted close from peer", peer.id);
           this.local.crashed = new Error("Unexpected close from peer");
           throw new Error("Unexpected close from peer");
         }
       })
       .catch((e) => {
-        console.error("Error processing messages from peer", peer.id, e);
+        logger.error("Error processing messages from peer", peer.id, e);
         if (peer.crashOnClose) {
           this.local.crashed = e;
           throw new Error(e);
@@ -406,13 +400,13 @@ export class SyncManager {
         // where we can get informations about the coValue
         if (msg.header || Object.keys(msg.sessions).length > 0) {
           entry.loadFromPeers([peer]).catch((e) => {
-            console.error("Error loading coValue in handleLoad", e);
+            logger.error("Error loading coValue in handleLoad", e);
           });
         }
         return;
       } else {
         this.local.loadCoValueCore(msg.id, peer.id).catch((e) => {
-          console.error("Error loading coValue in handleLoad", e);
+          logger.error("Error loading coValue in handleLoad", e);
         });
       }
     }
@@ -439,7 +433,7 @@ export class SyncManager {
               header: false,
               sessions: {},
             }).catch((e) => {
-              console.error("Error sending known state back", e);
+              logger.error("Error sending known state back", e);
             });
 
             return;
@@ -449,7 +443,7 @@ export class SyncManager {
           await this.sendNewContentIncludingDependencies(msg.id, peer);
         })
         .catch((e) => {
-          console.error("Error loading coValue in handleLoad loading state", e);
+          logger.error("Error loading coValue in handleLoad loading state", e);
         });
     }
 
@@ -484,7 +478,7 @@ export class SyncManager {
               peer.role === "storage" ? undefined : peer.id,
             )
             .catch((e) => {
-              console.error(
+              logger.error(
                 `Error loading coValue ${msg.id} to create loading state, as dependency of ${msg.asDependencyOf}`,
                 e,
               );
@@ -521,7 +515,7 @@ export class SyncManager {
 
     if (entry.state.type !== "available") {
       if (!msg.header) {
-        console.error("Expected header to be sent in first message");
+        logger.error("Expected header to be sent in first message");
         return;
       }
 
@@ -584,7 +578,7 @@ export class SyncManager {
               : t.changes.length,
           )
           .reduce((a, b) => a + b, 0);
-        console.log(
+        logger.debug(
           `Adding incoming transactions took ${(after - before).toFixed(
             2,
           )}ms for ${totalTxLength} bytes = bandwidth: ${(
@@ -602,7 +596,7 @@ export class SyncManager {
       // );
 
       if (result.isErr()) {
-        console.error(
+        logger.error(
           "Failed to add transactions from",
           peer.id,
           result.error,
@@ -633,7 +627,7 @@ export class SyncManager {
         isCorrection: true,
         ...coValue.knownState(),
       }).catch((e) => {
-        console.error("Error sending known state correction", e);
+        logger.error("Error sending known state correction", e);
       });
     } else {
       /**
@@ -647,7 +641,7 @@ export class SyncManager {
         action: "known",
         ...coValue.knownState(),
       }).catch((e: unknown) => {
-        console.error("Error sending known state", e);
+        logger.error("Error sending known state", e);
       });
     }
 
@@ -681,9 +675,6 @@ export class SyncManager {
       const done = new Promise<void>((resolve) => {
         queueMicrotask(async () => {
           delete this.requestedSyncs[coValue.id];
-          // if (entry.nRequestsThisTick >= 2) {
-          //     console.log("Syncing", coValue.id, "for", entry.nRequestsThisTick, "requests");
-          // }
           await this.actuallySyncCoValue(coValue);
           resolve();
         });

packages/cojson/src/tests/PeerState.test.ts

@@ -49,12 +49,9 @@ describe("PeerState", () => {
 
   test("should perform graceful shutdown", () => {
     const { mockPeer, peerState } = setup();
-    const consoleSpy = vi.spyOn(console, "debug").mockImplementation(() => {});
     peerState.gracefulShutdown();
     expect(mockPeer.outgoing.close).toHaveBeenCalled();
     expect(peerState.closed).toBe(true);
-    expect(consoleSpy).toHaveBeenCalledWith("Gracefully closing", "test-peer");
-    consoleSpy.mockRestore();
   });
 
   test("should empty the queue when closing", async () => {

packages/cojson/src/tests/logger.test.ts

@@ -0,0 +1,145 @@
+import { describe, expect, test, vi } from "vitest";
+import { LogLevel, Logger } from "../logger";
+
+describe("Logger", () => {
+  describe("Log Level Filtering", () => {
+    test("should respect log level hierarchy", () => {
+      const mockLogSystem = {
+        debug: vi.fn(),
+        info: vi.fn(),
+        warn: vi.fn(),
+        error: vi.fn(),
+      };
+
+      const logger = new Logger(LogLevel.WARN, mockLogSystem);
+
+      logger.debug("Debug message");
+      logger.info("Info message");
+      logger.warn("Warning message");
+      logger.error("Error message");
+
+      expect(mockLogSystem.debug).not.toHaveBeenCalled();
+      expect(mockLogSystem.info).not.toHaveBeenCalled();
+      expect(mockLogSystem.warn).toHaveBeenCalledWith("Warning message");
+      expect(mockLogSystem.error).toHaveBeenCalledWith("Error message");
+    });
+
+    test("should pass additional arguments to log system", () => {
+      const mockLogSystem = {
+        debug: vi.fn(),
+        info: vi.fn(),
+        warn: vi.fn(),
+        error: vi.fn(),
+      };
+
+      const logger = new Logger(LogLevel.DEBUG, mockLogSystem);
+      const additionalArgs = [{ foo: "bar" }, 42, "extra"];
+
+      logger.debug("Debug message", ...additionalArgs);
+
+      expect(mockLogSystem.debug).toHaveBeenCalledWith(
+        "Debug message",
+        ...additionalArgs,
+      );
+    });
+  });
+
+  describe("Log System Configuration", () => {
+    test("should allow changing log level at runtime", () => {
+      const mockLogSystem = {
+        debug: vi.fn(),
+        info: vi.fn(),
+        warn: vi.fn(),
+        error: vi.fn(),
+      };
+
+      const logger = new Logger(LogLevel.ERROR, mockLogSystem);
+
+      logger.warn("Warning 1"); // Should not log
+      expect(mockLogSystem.warn).not.toHaveBeenCalled();
+
+      logger.setLevel(LogLevel.WARN);
+      logger.warn("Warning 2"); // Should log
+      expect(mockLogSystem.warn).toHaveBeenCalledWith("Warning 2");
+    });
+
+    test("should allow changing log system at runtime", () => {
+      const mockLogSystem1 = {
+        debug: vi.fn(),
+        info: vi.fn(),
+        warn: vi.fn(),
+        error: vi.fn(),
+      };
+
+      const mockLogSystem2 = {
+        debug: vi.fn(),
+        info: vi.fn(),
+        warn: vi.fn(),
+        error: vi.fn(),
+      };
+
+      const logger = new Logger(LogLevel.INFO, mockLogSystem1);
+
+      logger.info("Message 1");
+      expect(mockLogSystem1.info).toHaveBeenCalledWith("Message 1");
+      expect(mockLogSystem2.info).not.toHaveBeenCalled();
+
+      logger.setLogSystem(mockLogSystem2);
+      logger.info("Message 2");
+      expect(mockLogSystem2.info).toHaveBeenCalledWith("Message 2");
+      expect(mockLogSystem1.info).toHaveBeenCalledTimes(1);
+    });
+  });
+
+  describe("Default Console Log System", () => {
+    test("should use console methods by default", () => {
+      const consoleSpy = {
+        debug: vi.spyOn(console, "debug").mockImplementation(() => {}),
+        info: vi.spyOn(console, "info").mockImplementation(() => {}),
+        warn: vi.spyOn(console, "warn").mockImplementation(() => {}),
+        error: vi.spyOn(console, "error").mockImplementation(() => {}),
+      };
+
+      const logger = new Logger();
+      logger.setLevel(LogLevel.DEBUG);
+      const testMessage = "Test message";
+      const testArgs = [{ data: "test" }, 123];
+
+      logger.debug(testMessage, ...testArgs);
+      logger.info(testMessage, ...testArgs);
+      logger.warn(testMessage, ...testArgs);
+      logger.error(testMessage, ...testArgs);
+
+      expect(consoleSpy.debug).toHaveBeenCalledWith(testMessage, ...testArgs);
+      expect(consoleSpy.info).toHaveBeenCalledWith(testMessage, ...testArgs);
+      expect(consoleSpy.warn).toHaveBeenCalledWith(testMessage, ...testArgs);
+      expect(consoleSpy.error).toHaveBeenCalledWith(testMessage, ...testArgs);
+
+      // Cleanup
+      Object.values(consoleSpy).forEach((spy) => spy.mockRestore());
+    });
+  });
+
+  describe("Log Level NONE", () => {
+    test("should not log anything when level is NONE", () => {
+      const mockLogSystem = {
+        debug: vi.fn(),
+        info: vi.fn(),
+        warn: vi.fn(),
+        error: vi.fn(),
+      };
+
+      const logger = new Logger(LogLevel.NONE, mockLogSystem);
+
+      logger.debug("Debug message");
+      logger.info("Info message");
+      logger.warn("Warning message");
+      logger.error("Error message");
+
+      expect(mockLogSystem.debug).not.toHaveBeenCalled();
+      expect(mockLogSystem.info).not.toHaveBeenCalled();
+      expect(mockLogSystem.warn).not.toHaveBeenCalled();
+      expect(mockLogSystem.error).not.toHaveBeenCalled();
+    });
+  });
+});

packages/jazz-tools/src/tests/schemaUnion.test.ts

@@ -13,11 +13,29 @@ class BaseWidget extends CoMap {
   type = co.string;
 }
 
-class ButtonWidget extends BaseWidget {
+class RedButtonWidget extends BaseWidget {
   type = co.literal("button");
+  color = co.literal("red");
   label = co.string;
 }
 
+class BlueButtonWidget extends BaseWidget {
+  type = co.literal("button");
+  color = co.literal("blue");
+  label = co.string;
+}
+
+const ButtonWidget = SchemaUnion.Of<BaseWidget>((raw) => {
+  switch (raw.get("color")) {
+    case "red":
+      return RedButtonWidget;
+    case "blue":
+      return BlueButtonWidget;
+    default:
+      throw new Error(`Unknown button color: ${raw.get("color")}`);
+  }
+});
+
 class SliderWidget extends BaseWidget {
   type = co.literal("slider");
   min = co.number;
@@ -57,8 +75,8 @@ describe("SchemaUnion", () => {
   });
 
   it("should instantiate the correct subclass based on schema and provided data", async () => {
-    const buttonWidget = ButtonWidget.create(
-      { type: "button", label: "Submit" },
+    const buttonWidget = RedButtonWidget.create(
+      { type: "button", color: "red", label: "Submit" },
       { owner: me },
     );
     const sliderWidget = SliderWidget.create(
@@ -89,14 +107,14 @@ describe("SchemaUnion", () => {
       {},
     );
 
-    expect(loadedButtonWidget).toBeInstanceOf(ButtonWidget);
+    expect(loadedButtonWidget).toBeInstanceOf(RedButtonWidget);
     expect(loadedSliderWidget).toBeInstanceOf(SliderWidget);
     expect(loadedCheckboxWidget).toBeInstanceOf(CheckboxWidget);
   });
 
   it("should integrate with subscribeToCoValue correctly", async () => {
-    const buttonWidget = ButtonWidget.create(
-      { type: "button", label: "Submit" },
+    const buttonWidget = BlueButtonWidget.create(
+      { type: "button", color: "blue", label: "Submit" },
       { owner: me },
     );
     let currentValue = "Submit";
@@ -106,7 +124,7 @@ describe("SchemaUnion", () => {
       me,
       {},
       (value: BaseWidget) => {
-        if (value instanceof ButtonWidget) {
+        if (value instanceof BlueButtonWidget) {
           expect(value.label).toBe(currentValue);
         } else {
           throw new Error("Unexpected widget type");