Fix caching issue

Fixes #138

modules/utils/getNpmPackageInfo.js

@@ -15,21 +15,17 @@ function getNpmPackageInfo(packageName) {
       } else {
         fetchNpmPackageInfo(packageName).then(value => {
           if (value == null) {
-            resolve(null);
-
             // Cache 404s for 5 minutes. This prevents us from making
             // unnecessary requests to the registry for bad package names.
             // In the worst case, a brand new package's info will be
             // available within 5 minutes.
             cache.setex(key, 300, notFound);
+            resolve(null);
           } else {
-            resolve(value);
-
             // Cache valid package info for 1 minute. In the worst case,
             // new versions won't be available for 1 minute.
-            cache.setnx(key, JSON.stringify(value), (error, reply) => {
-              if (reply === 1) cache.expire(key, 60);
-            });
+            cache.setex(key, 60, JSON.stringify(value));
+            resolve(value);
           }
         }, reject);
       }