perf: precompute the WebSocket frames when broadcasting

Note:

- only packets without binary attachments are affected
- the permessage-deflate extension must be disabled (which is the default)

Related:

- socketio/socket.io-adapter@5f7b47d
- socketio/engine.io@5e34722

Author: darrachequesne

package-lock.json

@@ -49,8 +49,8 @@
     "accepts": "~1.3.4",
     "base64id": "~2.0.0",
     "debug": "~4.3.2",
-    "engine.io": "~6.2.1",
-    "socket.io-adapter": "~2.4.0",
+    "engine.io": "~6.3.1",
+    "socket.io-adapter": "~2.5.2",
     "socket.io-parser": "~4.2.1"
   },
   "devDependencies": {

package.json

@@ -498,4 +498,22 @@ describe("messaging many", () => {
         success(done, io, socket1, socket2, socket3);
       });
   });
+
+  it("should precompute the WebSocket frame when broadcasting", (done) => {
+    const io = new Server(0);
+    const socket = createClient(io, "/chat", {
+      transports: ["websocket"],
+    });
+    const partialDone = createPartialDone(2, successFn(done, io, socket));
+
+    io.of("/chat").on("connection", (s) => {
+      s.conn.once("packetCreate", (packet) => {
+        expect(packet.options.wsPreEncodedFrame).to.be.an(Array);
+        partialDone();
+      });
+      io.of("/chat").compress(false).emit("woot", "hi");
+    });
+
+    socket.on("woot", partialDone);
+  });
 });

test/messaging-many.ts

@@ -731,7 +731,7 @@ describe("socket", () => {
     });
   });
 
-  it("should enable compresion by default", (done) => {
+  it("should enable compression by default", (done) => {
     const io = new Server(0);
     const socket = createClient(io, "/chat");
 
@@ -740,11 +740,11 @@ describe("socket", () => {
         expect(packet.options.compress).to.be(true);
         success(done, io, socket);
       });
-      io.of("/chat").emit("woot", "hi");
+      s.emit("woot", "hi");
     });
   });
 
-  it("should disable compresion", (done) => {
+  it("should disable compression", (done) => {
     const io = new Server(0);
     const socket = createClient(io, "/chat");
 
@@ -753,7 +753,7 @@ describe("socket", () => {
         expect(packet.options.compress).to.be(false);
         success(done, io, socket);
       });
-      io.of("/chat").compress(false).emit("woot", "hi");
+      s.compress(false).emit("woot", "hi");
     });
   });