Merge branch 'development' into dev-section-redesign

* development: (62 commits)
  Fix linter error
  Upgrade ethereum-types
  Lint and update deps
  Be more explicit with falsiness
  Add type to cssRuleIfExists
  Fix issue where we throw if non-numeric characters are used in input
  Upgrade to more recent types, fix yarn.lock
  [fix]: [testnet-faucet] Exit 1 on build fail
  Explains tools we want them to use
  Add note about button
  Add dev-tools-pages bundles to gitignore
  Improve README
  Fix button and center
  Increase max bundle size for instant
  Add stuff
  Initial project scaffolding
  Change tslint config to remove conflicts with prettier
  fix: [testnet-faucet] Signing of orders
  Update the CHANGELOG
  Add comments for expiryBuffer
  ...

1 files changed, 31 insertions, 0 deletions

diff --git a/packages/instant/src/redux/reducer.ts b/packages/instant/src/redux/reducer.ts
new file mode 100644
index 000000000..5026895ae
--- /dev/null
+++ b/packages/instant/src/redux/reducer.ts
@@ -0,0 +1,31 @@
+import { BigNumber } from '@0xproject/utils';
+import * as _ from 'lodash';
+
+import { Action, ActionTypes } from '../types';
+
+export interface State {
+    ethUsdPrice?: string;
+    selectedAssetAmount?: BigNumber;
+}
+
+export const INITIAL_STATE: State = {
+    ethUsdPrice: undefined,
+    selectedAssetAmount: undefined,
+};
+
+export const reducer = (state: State = INITIAL_STATE, action: Action): State => {
+    switch (action.type) {
+        case ActionTypes.UPDATE_ETH_USD_PRICE:
+            return {
+                ...state,
+                ethUsdPrice: action.data,
+            };
+        case ActionTypes.UPDATE_SELECTED_ASSET_AMOUNT:
+            return {
+                ...state,
+                selectedAssetAmount: action.data,
+            };
+        default:
+            return state;
+    }
+};