chore: add jest for javascript testing

.babelrc

@@ -3,7 +3,7 @@
     [
       "env",
       {
-        "modules": false,
+        "modules": "commonjs",
         "targets": {
           "browsers": "> 1%",
           "uglify": true

.eslintrc.js

@@ -9,6 +9,7 @@ module.exports = {
   },
   "env": {
     "browser": true,
+    "jest": true,
   },
   "settings": {
     "import/resolver": {

package.json

@@ -24,6 +24,8 @@
   },
   "devDependencies": {
     "babel-eslint": "^8.2.3",
+    "babel-jest": "^23.4.0",
+    "babel-preset-env": "^1.7.0",
     "eslint": "^4.9.0",
     "eslint-config-airbnb": "^16.1.0",
     "eslint-config-prettier": "^2.9.0",
@@ -32,12 +34,25 @@
     "eslint-plugin-jsx-a11y": "^6.0.3",
     "eslint-plugin-prettier": "^2.6.0",
     "eslint-plugin-react": "^7.9.1",
+    "jest": "^23.4.1",
     "prettier": "^1.13.4",
     "react-svg-loader": "^2.1.0",
     "require-yaml": "^0.0.1",
     "webpack-dev-server": "2.11.2"
   },
   "scripts": {
-    "lint": "./node_modules/.bin/eslint --ext js --ext jsx app/javascript/"
+    "lint": "./node_modules/.bin/eslint --ext js --ext jsx app/javascript/",
+    "test": "jest"
+  },
+  "jest": {
+    "verbose": true,
+    "testURL": "http://localhost/",
+    "roots": [
+      "app/javascript"
+    ],
+    "moduleDirectories": [
+      "node_modules",
+      "app/javascript"
+    ]
   }
 }