perf(ext/websocket): efficient event kind serialization (#18509)

Use u16 to represent the kind of event (0 - 6) & event code > 6 is
treated as the close code. This way we can represent all events + the
close code in a single JS number. This is safe because (as per RFC 6455)
close code from 0-999 are reserved & not used.

| name | avg msg/sec/core |
| --- | --- |
| deno_main | `127820.750000` |
| deno #18506 | `140079.000000` |
| deno #18506 + this | `150104.250000` |

1 files changed, 33 insertions, 24 deletions

diff --git a/ext/websocket/01_websocket.js b/ext/websocket/01_websocket.js
index 06eb08b60..03a6427c2 100644
--- a/ext/websocket/01_websocket.js
+++ b/ext/websocket/01_websocket.js
@@ -394,13 +394,14 @@ class WebSocket extends EventTarget {
 
   async [_eventLoop]() {
     while (this[_readyState] !== CLOSED) {
-      const { kind, value } = await core.opAsync(
+      const { 0: kind, 1: value } = await core.opAsync(
         "op_ws_next_event",
         this[_rid],
       );
 
       switch (kind) {
-        case "string": {
+        case 0: {
+          /* string */
           this[_serverHandleIdleTimeout]();
           const event = new MessageEvent("message", {
             data: value,
@@ -409,14 +410,15 @@ class WebSocket extends EventTarget {
           this.dispatchEvent(event);
           break;
         }
-        case "binary": {
+        case 1: {
+          /* binary */
           this[_serverHandleIdleTimeout]();
           let data;
 
           if (this.binaryType === "blob") {
             data = new Blob([value]);
           } else {
-            data = value.buffer;
+            data = value;
           }
 
           const event = new MessageEvent("message", {
@@ -427,12 +429,32 @@ class WebSocket extends EventTarget {
           this.dispatchEvent(event);
           break;
         }
-        case "pong": {
+        case 2: {
+          /* pong */
           this[_serverHandleIdleTimeout]();
           break;
         }
-        case "closed":
-        case "close": {
+        case 5: {
+          /* error */
+          this[_readyState] = CLOSED;
+
+          const errorEv = new ErrorEvent("error", {
+            message: value,
+          });
+          this.dispatchEvent(errorEv);
+
+          const closeEv = new CloseEvent("close");
+          this.dispatchEvent(closeEv);
+          core.tryClose(this[_rid]);
+          break;
+        }
+        case 3: {
+          /* ping */
+          break;
+        }
+        default: {
+          /* close */
+          const code = kind;
           const prevState = this[_readyState];
           this[_readyState] = CLOSED;
           clearTimeout(this[_idleTimeoutTimeout]);
@@ -442,8 +464,8 @@ class WebSocket extends EventTarget {
               await core.opAsync(
                 "op_ws_close",
                 this[_rid],
-                value.code,
-                value.reason,
+                code,
+                value,
               );
             } catch {
               // ignore failures
@@ -452,26 +474,13 @@ class WebSocket extends EventTarget {
 
           const event = new CloseEvent("close", {
             wasClean: true,
-            code: value.code,
-            reason: value.reason,
+            code: code,
+            reason: value,
           });
           this.dispatchEvent(event);
           core.tryClose(this[_rid]);
           break;
         }
-        case "error": {
-          this[_readyState] = CLOSED;
-
-          const errorEv = new ErrorEvent("error", {
-            message: value,
-          });
-          this.dispatchEvent(errorEv);
-
-          const closeEv = new CloseEvent("close");
-          this.dispatchEvent(closeEv);
-          core.tryClose(this[_rid]);
-          break;
-        }
       }
     }
   }