Smarter balance fetching (#3605)

* Smarter dApps Manifest fetching...

* Fetching only visible accounts (and don't delete other balances) #3590

* Moved balances action into BalancesActions #3590

* Fetch balances for accounts and contracts #3590

* Add balances to contract/address/account views #3590

* Fix transaction not fetching on first load

* Remove console.warn

* Fix pending tokens not showing #3154

* Fix tokens image update

* Remove unused name in Header

* Separate Tokens and ETH fetching #3590

* Remove unused isTest

* Fetch Tokens Balance via Filter #3590

* Fix linting

* Fix updating tokens image (#3590)

* Fix contract balances

* Improved Status

* Fixing secureApi issues...

* Fetch all tokens every 2 minutes (for safety) #3590

* PR changes fix

* Fix Account error

js/src/views/Dapps/dappsStore.js

@@ -32,6 +32,8 @@ export default class DappsStore {
   @observable modalOpen = false;
   @observable externalOverlayVisible = true;
 
+  _manifests = {};
+
   constructor (api) {
     this._api = api;
 
@@ -249,12 +251,27 @@ export default class DappsStore {
   }
 
   _fetchManifest (manifestHash) {
+    if (/^(0x)?0+/.test(manifestHash)) {
+      return Promise.resolve(null);
+    }
+
+    if (this._manifests[manifestHash]) {
+      return Promise.resolve(this._manifests[manifestHash]);
+    }
+
     return fetch(`${this._getHost()}/api/content/${manifestHash}/`, { redirect: 'follow', mode: 'cors' })
       .then((response) => {
         return response.ok
           ? response.json()
           : null;
       })
+      .then((manifest) => {
+        if (manifest) {
+          this._manifests[manifestHash] = manifest;
+        }
+
+        return manifest;
+      })
       .catch((error) => {
         console.warn('DappsStore:fetchManifest', error);
         return null;