2 files changed, 48 insertions, 4 deletions
diff --git a/app/scripts/controllers/preferences.js b/app/scripts/controllers/preferences.js
index bc4848421..c42f47037 100644
--- a/app/scripts/controllers/preferences.js
+++ b/app/scripts/controllers/preferences.js
@@ -26,23 +26,23 @@ class PreferencesController {
     return this.store.getState().selectedAddress
   }
 
-  addToken (rawAddress, symbol, decimals) {
+  async addToken (rawAddress, symbol, decimals) {
     const address = normalizeAddress(rawAddress)
     const newEntry = { address, symbol, decimals }
 
     const tokens = this.store.getState().tokens
-    const previousIndex = tokens.find((token, index) => {
+    const previousEntry = tokens.find((token, index) => {
       return token.address === address
     })
+    const previousIndex = tokens.indexOf(previousEntry)
 
-    if (previousIndex) {
+    if (previousEntry) {
       tokens[previousIndex] = newEntry
     } else {
       tokens.push(newEntry)
     }
 
     this.store.updateState({ tokens })
-    return Promise.resolve()
   }
 
   getTokens () {
diff --git a/app/scripts/controllers/recent-blocks.js b/app/scripts/controllers/recent-blocks.js
new file mode 100644
index 000000000..4a906261e
--- /dev/null
+++ b/app/scripts/controllers/recent-blocks.js
@@ -0,0 +1,44 @@
+const ObservableStore = require('obs-store')
+const extend = require('xtend')
+
+class RecentBlocksController {
+
+  constructor (opts = {}) {
+    const { blockTracker } = opts
+    this.blockTracker = blockTracker
+    this.historyLength = opts.historyLength || 40
+
+    const initState = extend({
+      recentBlocks: [],
+    }, opts.initState)
+    this.store = new ObservableStore(initState)
+
+    this.blockTracker.on('block', this.processBlock.bind(this))
+  }
+
+  resetState () {
+    this.store.updateState({
+      recentBlocks: [],
+    })
+  }
+
+  processBlock (newBlock) {
+    const block = extend(newBlock, {
+      gasPrices: newBlock.transactions.map((tx) => {
+        return tx.gasPrice
+      }),
+    })
+    delete block.transactions
+
+    const state = this.store.getState()
+    state.recentBlocks.push(block)
+
+    while (state.recentBlocks.length > this.historyLength) {
+      state.recentBlocks.shift()
+    }
+
+    this.store.updateState(state)
+  }
+}
+
+module.exports = RecentBlocksController