feat: Emit close event on http.ServerResponse (#263)

feat: Emit all events written from socket to resposne, instead assuming emitter in serverless-http

feat: Use response#finish event to trigger socket end, instead of vice-versa

feat: Clean up emitter, use once

lib/response.js

@@ -126,6 +126,10 @@ module.exports = class ServerlessResponse extends http.ServerResponse {
         }
       },
     });
+
+    this.once('finish', () => {
+      this.emit('close')
+    });
   }
 
 };

test/generic.js

@@ -3,7 +3,8 @@
 const url = require('url'),
   fs = require('fs'),
   expect = require('chai').expect,
-  request = require('./util/request');
+  request = require('./util/request'),
+  sinon = require('sinon');
 
 describe('generic http listener', () => {
   let app;
@@ -153,4 +154,21 @@ describe('generic http listener', () => {
       });
     });
   });
+
+  it('should emit close once', () => {
+    const stub = sinon.stub().returns(true);
+    app = function (req, res) {
+      res.on('close', stub);
+      res.writeHead(200);
+      res.emit('finish'); // Test multiple finish deliveries
+      res.end();
+    };
+
+    return request(app, {
+      httpMethod: 'GET',
+      path: '/',
+    }).then(() => {
+      expect(stub.calledOnce).to.be.true;
+    });
+  });
 });