Convert babel config to JS for Jest to pick up

babel.config.js

@@ -0,0 +1,25 @@
+module.exports = {
+  "sourceMaps": true,
+  "presets": [
+    ["@babel/preset-env", {
+      "targets": {
+        "browsers": [
+          "last 2 versions"
+        ]
+      }
+    }],
+    "@babel/preset-typescript",
+    "@babel/preset-flow",
+    "@babel/preset-react"
+  ],
+  "plugins": [
+    ["@babel/plugin-proposal-decorators", {"legacy": true}],
+    "@babel/plugin-proposal-export-default-from",
+    "@babel/plugin-proposal-numeric-separator",
+    "@babel/plugin-proposal-class-properties",
+    "@babel/plugin-proposal-object-rest-spread",
+    "@babel/plugin-transform-flow-comments",
+    "@babel/plugin-syntax-dynamic-import",
+    "@babel/plugin-transform-runtime"
+  ]
+};