diff --git a/lib/client.js b/lib/client.js
index 62b2d38..1c19623 100644
--- a/lib/client.js
+++ b/lib/client.js
@@ -1,3 +1,5 @@
+'use strict';
+
 const EventEmitter = require('events');
 const crypto = require('crypto');
 
@@ -263,7 +265,7 @@ class Client extends EventEmitter {
    */
   get(url, data, callback) {
     if (!url) {
-      throw new Error('url is required');
+      return Promise.reject(new Error('url is required'));
     }
 
     if (typeof data === 'function') {
@@ -277,10 +279,8 @@ class Client extends EventEmitter {
     }
 
     if (!this.authed) {
-      return new Promise((resolve) => {
-        // If not connected, do auth to get updated versions first
-        this.getPendingAuth(url, data, callback, resolve);
-      });
+      // If not connected, do auth to get updated versions first
+      return this.getPendingAuth(url, data, callback);
     }
 
     // Indicates whether to check the request cache or not
@@ -301,23 +301,35 @@ class Client extends EventEmitter {
     return this.request('get', url, data, callback);
   }
 
-  getPendingAuth(url, data, callback, resolve) {
-    if (this.requestsPendingAuth) {
-      this.requestsPendingAuth.push({ url, data, callback, resolve });
-      return;
-    }
+  getPendingAuth(url, data, callback) {
+    return new Promise((resolve, reject) => {
+      if (this.requestsPendingAuth) {
+        this.requestsPendingAuth.push({ url, data, callback, resolve });
+        return;
+      }
 
-    this.requestsPendingAuth = [];
+      this.requestsPendingAuth = [];
 
-    this.authWithKey(() => {
-      this.get(url, data, (_err, result, headers) => {
-        if (callback) {
-          callback(null, result, headers);
-        }
-        resolve(result);
-      });
+      this.authWithKey(() => {
+        this.get(url, data, (err, result, headers) => {
+          if (typeof callback === 'function') {
+            callback(err, result, headers);
+          }
 
+          if (err) {
+            reject(err);
+            return;
+          }
+
+          resolve(result);
+        })
+        .catch((err) => {
+          reject(err.message);
+        });
+      });
+    }).then((result) => {
       this.flushRequestsPendingAuth();
+      return result;
     });
   }
 
diff --git a/lib/connection.js b/lib/connection.js
index 9b4ad3a..9fc52b9 100644
--- a/lib/connection.js
+++ b/lib/connection.js
@@ -1,3 +1,5 @@
+'use strict';
+
 const EventEmitter = require('events');
 const tls = require('tls');
 const net = require('net');