Preserving user's queryString

Fixes: #272

client-ts/Microsoft.AspNetCore.SignalR.Client.TS.Tests/Connection.spec.ts

@@ -1,6 +1,8 @@
 import { IHttpClient } from "../Microsoft.AspNetCore.SignalR.Client.TS/HttpClient"
 import { Connection } from "../Microsoft.AspNetCore.SignalR.Client.TS/Connection"
 import { ISignalROptions } from "../Microsoft.AspNetCore.SignalR.Client.TS/ISignalROptions"
+import { DataReceived, TransportClosed } from "../Microsoft.AspNetCore.SignalR.Client.TS/Common"
+import { ITransport } from "../Microsoft.AspNetCore.SignalR.Client.TS/Transports"
 
 describe("Connection", () => {
 
@@ -122,4 +124,44 @@ describe("Connection", () => {
         await connection.stop();
         done();
     });
+
+    it("preserves users connection string", async done => {
+        let options: ISignalROptions = {
+            httpClient: <IHttpClient>{
+                get(url: string): Promise<string> {
+                    if (url.includes("negotiate")) {
+                        return Promise.resolve("42");
+                    }
+                    return Promise.resolve("");
+                }
+            }
+        } as ISignalROptions;
+
+        let connectQueryString: string;
+        let fakeTransport: ITransport = {
+            connect(url: string, queryString: string): Promise<void> {
+                connectQueryString = queryString;
+                return Promise.reject("");
+            },
+            send(data: any): Promise<void> {
+                return Promise.reject("");
+            },
+            stop(): void { },
+            onDataReceived: undefined,
+            onClosed: undefined
+        }
+
+        var connection = new Connection("http://tempuri.org", "q=myData", options);
+
+        try {
+            await connection.start(fakeTransport);
+            fail();
+            done();
+        }
+        catch (e) {
+        }
+
+        expect(connectQueryString).toBe("q=myData&id=42");
+        done();
+    });
 });

client-ts/Microsoft.AspNetCore.SignalR.Client.TS/Connection.ts

@@ -22,7 +22,7 @@ export class Connection implements IConnection {
 
     constructor(url: string, queryString: string = "", options: ISignalROptions = {}) {
         this.url = url;
-        this.queryString = queryString;
+        this.queryString = queryString || "";
         this.httpClient = options.httpClient || new HttpClient();
         this.connectionState = ConnectionState.Initial;
     }
@@ -47,7 +47,10 @@ export class Connection implements IConnection {
                 return;
             }
 
-            this.queryString = `id=${this.connectionId}`;
+            if (this.queryString) {
+                this.queryString += "&";
+            }
+            this.queryString += `id=${this.connectionId}`;
 
             this.transport = this.createTransport(transportType);
             this.transport.onDataReceived = this.onDataReceived;