refactor all redis calls to reject on null

public/main.css

@@ -1,8 +1,7 @@
 /***     index.html     ***/
 html {
   background: url('resources/send_bg.svg');
-  font-family:
-    -apple-system,
+  font-family: -apple-system,
     BlinkMacSystemFont,
     'SF Pro Text',
     Helvetica,

server/storage.js

@@ -27,7 +27,6 @@ if (conf.s3_bucket) {
     length: awsLength,
     get: awsGet,
     set: awsSet,
-    aad: aad,
     setField: setField,
     delete: awsDelete,
     forceDelete: awsForceDelete,
@@ -44,7 +43,6 @@ if (conf.s3_bucket) {
     length: localLength,
     get: localGet,
     set: localSet,
-    aad: aad,
     setField: setField,
     delete: localDelete,
     forceDelete: localForceDelete,
@@ -66,11 +64,10 @@ function quit() {
 function metadata(id) {
   return new Promise((resolve, reject) => {
     redis_client.hgetall(id, (err, reply) => {
-      if (!err) {
-        resolve(reply);
-      } else {
-        reject(err);
+      if (err || !reply) {
+        return reject(err);
       }
+      resolve(reply);
     });
   });
 }
@@ -78,11 +75,10 @@ function metadata(id) {
 function ttl(id) {
   return new Promise((resolve, reject) => {
     redis_client.ttl(id, (err, reply) => {
-      if (!err) {
-        resolve(reply * 1000);
-      } else {
-        reject(err);
+      if (err || !reply) {
+        return reject(err);
       }
+      resolve(reply * 1000);
     });
   });
 }
@@ -114,18 +110,6 @@ function setField(id, key, value) {
   redis_client.hset(id, key, value);
 }
 
-function aad(id) {
-  return new Promise((resolve, reject) => {
-    redis_client.hget(id, 'aad', (err, reply) => {
-      if (!err) {
-        resolve(reply);
-      } else {
-        reject();
-      }
-    });
-  });
-}
-
 function localLength(id) {
   return new Promise((resolve, reject) => {
     try {