lib: rewrite i-face introspection without promises

PR-URL: #245
Reviewed-By: Alexey Orlenko <eaglexrlnk@gmail.com>
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Mykola Bilochub <nbelochub@gmail.com>

lib/transport-common.js

@@ -68,25 +68,23 @@ const newConnectAndInspectFn = (connFactory, transportClass) => {
     const callback = common.extractCallback(options);
     connect(appName, client, ...options, (error, connection) => {
       if (error) return callback(error);
-
-      Promise.all(interfaces.map(name => new Promise((resolve, reject) => {
-        connection.inspectInterface(name, (error, proxy) => {
-          if (error) {
-            reject(error);
-          } else {
-            resolve(proxy);
+      const proxies = Object.create(null);
+      let errored = false;
+      const len = interfaces.length;
+      let count = 0;
+      interfaces.forEach(name => connection.inspectInterface(name,
+        (error, proxy) => {
+          if (!errored) {
+            count++;
+            if (error) {
+              errored = true;
+              return callback(error, connection);
+            }
+            proxies[name] = proxy;
+            if (count === len) callback(null, connection, proxies);
           }
-        });
-      }))).then((proxies) => {
-        const api = proxies.reduce((acc, proxy, idx) => {
-          const name = interfaces[idx];
-          acc[name] = proxy;
-          return acc;
-        }, Object.create(null));
-        callback(null, connection, api);
-      }).catch((error) => {
-        callback(error, connection);
-      });
+        }
+      ));
     });
   };
 };