Add new "has" method

browser-sync/browser-sync-tests.ts

@@ -78,6 +78,8 @@ evt.on("init", function () {
 
 browserSync(config);
 
+var has = browserSync.has("My server");
+
 var bs = browserSync.create();
 
 bs.init({

browser-sync/browser-sync.d.ts

@@ -335,6 +335,11 @@ declare module "browser-sync" {
              * @param name the identifier used for retrieval
              */
             get(name: string): BrowserSyncInstance;
+            /**
+             * Check if an instance has been created.
+             * @param name the name of the instance
+             */
+            has(name: string): boolean;
         }
 
         interface BrowserSyncInstance {