fix(node:http/node:https) emit continue (#13434)

src/js/node/http.ts

@@ -1133,6 +1133,16 @@ Object.defineProperty(OutgoingMessage.prototype, "finished", {
   },
 });
 
+function emitContinueAndSocketNT(self) {
+  if (self.destroyed) return;
+  // Ref: https://github.com/nodejs/node/blob/f63e8b7fa7a4b5e041ddec67307609ec8837154f/lib/_http_client.js#L803-L839
+  self.emit("socket", self.socket);
+
+  //Emit continue event for the client (internally we auto handle it)
+  if (!self._closed && self.getHeader("expect") === "100-continue") {
+    self.emit("continue");
+  }
+}
 function emitCloseNT(self) {
   if (!self._closed) {
     self._closed = true;
@@ -1888,11 +1898,7 @@ class ClientRequest extends OutgoingMessage {
 
     this._httpMessage = this;
 
-    process.nextTick(() => {
-      // Ref: https://github.com/nodejs/node/blob/f63e8b7fa7a4b5e041ddec67307609ec8837154f/lib/_http_client.js#L803-L839
-      if (this.destroyed) return;
-      this.emit("socket", this.socket);
-    });
+    process.nextTick(emitContinueAndSocketNT, this);
   }
 
   setSocketKeepAlive(enable = true, initialDelay = 0) {

test/js/node/http/node-http.test.ts

@@ -2252,3 +2252,50 @@ it.skip("should be able to stream huge amounts of data", async () => {
     server.close();
   }
 }, 30_000);
+
+// TODO: today we use a workaround to continue event, we need to fix it in the future.
+it("should emit continue event #7480", done => {
+  let receivedContinue = false;
+  const req = request(
+    "https://example.com",
+    { headers: { "accept-encoding": "identity", "expect": "100-continue" } },
+    res => {
+      let data = "";
+      res.setEncoding("utf8");
+      res.on("data", chunk => {
+        data += chunk;
+      });
+      res.on("end", () => {
+        expect(receivedContinue).toBe(true);
+        expect(data).toContain("This domain is for use in illustrative examples in documents");
+        done();
+      });
+      res.on("error", err => done(err));
+    },
+  );
+  req.on("continue", () => {
+    receivedContinue = true;
+  });
+  req.end();
+});
+
+it("should not emit continue event #7480", done => {
+  let receivedContinue = false;
+  const req = request("https://example.com", { headers: { "accept-encoding": "identity" } }, res => {
+    let data = "";
+    res.setEncoding("utf8");
+    res.on("data", chunk => {
+      data += chunk;
+    });
+    res.on("end", () => {
+      expect(receivedContinue).toBe(false);
+      expect(data).toContain("This domain is for use in illustrative examples in documents");
+      done();
+    });
+    res.on("error", err => done(err));
+  });
+  req.on("continue", () => {
+    receivedContinue = true;
+  });
+  req.end();
+});