Fix levelDb error

.gitignore

@@ -1,3 +1,5 @@
 dist
 node_modules
-tmp
+tmp
+# Level db database
+*dbDir*

bin/utils.js

@@ -144,12 +144,13 @@ class WSSharedDoc extends Y.Doc {
  */
 const getYDoc = (docname, gc = true) => map.setIfUndefined(docs, docname, () => {
   const doc = new WSSharedDoc(docname)
+  let docLoadedPromise = null
   doc.gc = gc
   if (persistence !== null) {
-    persistence.bindState(docname, doc)
+    docLoadedPromise = persistence.bindState(docname, doc)
   }
   docs.set(docname, doc)
-  return doc
+  return { doc, docLoadedPromise }
 })
 
 exports.getYDoc = getYDoc
@@ -237,17 +238,28 @@ const pingTimeout = 30000
 exports.setupWSConnection = (conn, req, { docName = req.url.slice(1).split('?')[0], gc = true } = {}) => {
   conn.binaryType = 'arraybuffer'
   // get doc, initialize if it does not exist yet
-  const doc = getYDoc(docName, gc)
+  const { doc, docLoadedPromise } = getYDoc(docName, gc)
   doc.conns.set(conn, new Set())
+
+  // it might take some time to load the doc from leveldb
+  // but before then we still need to listen for websocket events
+  let isDocLoaded = docLoadedPromise ? false : true
+  let queuedMessages = []
+  let isConnectionAlive = true
+
   // listen and reply to events
-  conn.on('message', /** @param {ArrayBuffer} message */ message => messageListener(conn, doc, new Uint8Array(message)))
+  conn.on('message', /** @param {ArrayBuffer} message */ message => {
+    if (isDocLoaded) messageListener(conn, doc, new Uint8Array(message))
+    else queuedMessages.push(new Uint8Array(message))
+  })
 
   // Check if connection is still alive
   let pongReceived = true
   const pingInterval = setInterval(() => {
     if (!pongReceived) {
       if (doc.conns.has(conn)) {
         closeConn(doc, conn)
+        isConnectionAlive = false
       }
       clearInterval(pingInterval)
     } else if (doc.conns.has(conn)) {
@@ -256,20 +268,22 @@ exports.setupWSConnection = (conn, req, { docName = req.url.slice(1).split('?')[
         conn.ping()
       } catch (e) {
         closeConn(doc, conn)
+        isConnectionAlive = false
         clearInterval(pingInterval)
       }
     }
   }, pingTimeout)
   conn.on('close', () => {
     closeConn(doc, conn)
+    isConnectionAlive = false
     clearInterval(pingInterval)
   })
   conn.on('pong', () => {
     pongReceived = true
   })
   // put the following in a variables in a block so the interval handlers don't keep in in
   // scope
-  {
+  const sendSyncStep1 = () =>{
     // send sync step 1
     const encoder = encoding.createEncoder()
     encoding.writeVarUint(encoder, messageSync)
@@ -283,4 +297,15 @@ exports.setupWSConnection = (conn, req, { docName = req.url.slice(1).split('?')[
       send(doc, conn, encoding.toUint8Array(encoder))
     }
   }
+
+  if (docLoadedPromise) {
+    docLoadedPromise.then(() => {
+      if (!isConnectionAlive) return
+
+      isDocLoaded = true
+      queuedMessages.forEach(message => messageListener(conn, doc, message))
+      queuedMessages = null
+      sendSyncStep1()
+    })
+  }
 }

package.json

@@ -11,7 +11,7 @@
     "url": "https://github.com/sponsors/dmonad"
   },
   "scripts": {
-    "start": "node ./bin/server.js",
+    "start": "HOST=localhost PORT=1234 YPERSISTENCE=./dbDir node ./bin/server.js",
     "dist": "rm -rf dist && rollup -c && tsc",
     "lint": "standard && tsc",
     "test": "npm run lint",