Add Recent Blocks controller

Tracks recent blocks, useful for estimating recent successful gas
prices.

1 files changed, 37 insertions, 0 deletions

diff --git a/app/scripts/controllers/recent-blocks.js b/app/scripts/controllers/recent-blocks.js
new file mode 100644
index 000000000..27f9013ff
--- /dev/null
+++ b/app/scripts/controllers/recent-blocks.js
@@ -0,0 +1,37 @@
+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 state = this.store.getState()
+    state.recentBlocks.push(newBlock)
+
+    while (state.recentBlocks.length > this.historyLength) {
+      state.recentBlocks.shift()
+    }
+
+    this.store.updateState(state)
+  }
+}
+
+module.exports = RecentBlocksController