[fix] Make WebSocket#close() work when called from a headers listener

lib/WebSocket.js

@@ -653,10 +653,16 @@ function initAsClient (address, protocols, options) {
   });
 
   this._req.on('upgrade', (res, socket, head) => {
-    this._req = null;
-
     this.emit('headers', res.headers, res);
 
+    //
+    // The user may have closed the connection from a listener of the `headers`
+    // event.
+    //
+    if (this.readyState !== WebSocket.CONNECTING) return;
+
+    this._req = null;
+
     const digest = crypto.createHash('sha1')
       .update(key + constants.GUID, 'binary')
       .digest('base64');

test/WebSocket.test.js

@@ -999,6 +999,20 @@ describe('WebSocket', function () {
       });
     });
 
+    it('can be called from a listener of the headers event', function (done) {
+      const wss = new WebSocketServer({ port: ++port }, () => {
+        const ws = new WebSocket(`ws://localhost:${port}`);
+
+        ws.on('open', () => assert.fail(null, null, 'connect shouldnt be raised here'));
+        ws.on('error', (err) => {
+          assert.ok(err instanceof Error);
+          assert.strictEqual(err.message, 'closed before the connection is established');
+          ws.on('close', () => wss.close(done));
+        });
+        ws.on('headers', () => ws.close());
+      });
+    });
+
     it('throws an error if the first argument is invalid (1/2)', function (done) {
       const wss = new WebSocketServer({ port: ++port }, () => {
         const ws = new WebSocket(`ws://localhost:${port}`);
@@ -1209,6 +1223,20 @@ describe('WebSocket', function () {
       });
     });
 
+    it('can be called from a listener of the headers event', function (done) {
+      const wss = new WebSocketServer({ port: ++port }, () => {
+        const ws = new WebSocket(`ws://localhost:${port}`);
+
+        ws.on('open', () => assert.fail(null, null, 'connect shouldnt be raised here'));
+        ws.on('error', (err) => {
+          assert.ok(err instanceof Error);
+          assert.strictEqual(err.message, 'closed before the connection is established');
+          ws.on('close', () => wss.close(done));
+        });
+        ws.on('headers', () => ws.terminate());
+      });
+    });
+
     it('does nothing if the connection is already CLOSED', function (done) {
       const wss = new WebSocketServer({ port: ++port }, () => {
         const ws = new WebSocket(`ws://localhost:${port}`);