Use babel-polyfill to fix error

main.ts

@@ -1,3 +1,6 @@
+// This allows us to have async/await in our code. It must be loaded first.
+import "babel-polyfill";
+
 import * as dispatch from "./dispatch";
 import { main as pb } from "./msg.pb";
 

package.json

@@ -8,6 +8,7 @@
   "devDependencies": {
     "@types/base64-js": "^1.2.5",
     "@types/source-map-support": "^0.4.0",
+    "babel-polyfill": "^6.26.0",
     "base64-js": "^1.3.0",
     "espree": "^3.5.3",
     "jsdoc": "^3.5.5",

yarn.lock

@@ -583,6 +583,14 @@ babel-plugin-transform-strict-mode@^6.24.1:
     babel-runtime "^6.22.0"
     babel-types "^6.24.1"
 
+babel-polyfill@^6.26.0:
+  version "6.26.0"
+  resolved "https://registry.yarnpkg.com/babel-polyfill/-/babel-polyfill-6.26.0.tgz#379937abc67d7895970adc621f284cd966cf2153"
+  dependencies:
+    babel-runtime "^6.26.0"
+    core-js "^2.5.0"
+    regenerator-runtime "^0.10.5"
+
 babel-preset-env@^1.6.1:
   version "1.7.0"
   resolved "https://registry.yarnpkg.com/babel-preset-env/-/babel-preset-env-1.7.0.tgz#dea79fa4ebeb883cd35dab07e260c1c9c04df77a"
@@ -3073,6 +3081,10 @@ regenerate@^1.2.1:
   version "1.4.0"
   resolved "https://registry.yarnpkg.com/regenerate/-/regenerate-1.4.0.tgz#4a856ec4b56e4077c557589cae85e7a4c8869a11"
 
+regenerator-runtime@^0.10.5:
+  version "0.10.5"
+  resolved "https://registry.yarnpkg.com/regenerator-runtime/-/regenerator-runtime-0.10.5.tgz#336c3efc1220adcedda2c9fab67b5a7955a33658"
+
 regenerator-runtime@^0.11.0:
   version "0.11.1"
   resolved "https://registry.yarnpkg.com/regenerator-runtime/-/regenerator-runtime-0.11.1.tgz#be05ad7f9bf7d22e056f9726cee5017fbf19e2e9"