Setting NODE_ENV for builds

package.json

@@ -13,7 +13,7 @@
     "start": "webpack-dev-server --config webpack.dev.js",
     "start:prod": "run-s build start:http-server",
     "start:http-server": "http-server ./build",
-    "build": "run-s build:webpack build:prerender",
+    "build": "cross-env NODE_ENV=production run-s build:webpack build:prerender",
     "build:webpack": "webpack --config webpack.prod.js",
     "build:prerender": "node ./prerender/prerender.js",
     "test": "run-s test:lint 'test:unit --coverage'",
@@ -59,6 +59,7 @@
     "babel-register": "^6.26.0",
     "cheerio": "^1.0.0-rc.2",
     "copy-webpack-plugin": "^4.4.1",
+    "cross-env": "^5.1.3",
     "css-loader": "^0.28.9",
     "enzyme": "^3.3.0",
     "enzyme-adapter-react-16": "^1.1.1",

yarn.lock

@@ -1846,6 +1846,13 @@ create-hmac@^1.1.0, create-hmac@^1.1.2, create-hmac@^1.1.4:
     safe-buffer "^5.0.1"
     sha.js "^2.4.8"
 
+cross-env@^5.1.3:
+  version "5.1.3"
+  resolved "https://registry.yarnpkg.com/cross-env/-/cross-env-5.1.3.tgz#f8ae18faac87692b0a8b4d2f7000d4ec3a85dfd7"
+  dependencies:
+    cross-spawn "^5.1.0"
+    is-windows "^1.0.0"
+
 cross-spawn@^5.0.1, cross-spawn@^5.1.0:
   version "5.1.0"
   resolved "https://registry.yarnpkg.com/cross-spawn/-/cross-spawn-5.1.0.tgz#e8bd0efee58fcff6f8f94510a0a554bbfa235449"
@@ -4089,6 +4096,10 @@ is-utf8@^0.2.0:
   version "0.2.1"
   resolved "https://registry.yarnpkg.com/is-utf8/-/is-utf8-0.2.1.tgz#4b0da1442104d1b336340e80797e865cf39f7d72"
 
+is-windows@^1.0.0:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/is-windows/-/is-windows-1.0.1.tgz#310db70f742d259a16a369202b51af84233310d9"
+
 is-wsl@^1.1.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/is-wsl/-/is-wsl-1.1.0.tgz#1f16e4aa22b04d1336b66188a66af3c600c3a66d"