build: fix build commands on Windows (#155)

Fixes #147

Author: FezVrasta

package.json

@@ -16,8 +16,8 @@
   "scripts": {
     "build": "npm run build:clean && npm run build:es && npm run build:cjs && npm run build:flow",
     "build:clean": "rimraf dist/ && rimraf lib/",
-    "build:es": "BABEL_ENV=es babel src --ignore '*.test.js,__mocks__' --out-dir lib/es",
-    "build:cjs": "BABEL_ENV=cjs babel src --ignore '*.test.js,__mocks__' --out-dir lib/cjs",
+    "build:es": "cross-env BABEL_ENV=es babel src --ignore '*.test.js,__mocks__' --out-dir lib/es",
+    "build:cjs": "cross-env BABEL_ENV=cjs babel src --ignore '*.test.js,__mocks__' --out-dir lib/cjs",
     "build:flow": "flow-copy-source --ignore '{__mocks__/*,*.test}.js' src lib/es",
     "demo:dev": "parcel --out-dir demo/dist demo/index.html",
     "demo:build": "parcel build --out-dir demo/dist demo/index.html --public-url=/react-popper",
@@ -76,6 +76,7 @@
     "babel-preset-env": "^1.6.1",
     "babel-preset-react": "^6.24.1",
     "babel-preset-stage-1": "^6.24.1",
+    "cross-env": "^5.1.4",
     "emotion": "^9.1.1",
     "enzyme": "^3.3.0",
     "enzyme-adapter-react-16": "^1.1.1",

yarn.lock

@@ -1767,6 +1767,13 @@ create-react-context@^0.2.1:
     fbjs "^0.8.0"
     gud "^1.0.0"
 
+cross-env@^5.1.4:
+  version "5.1.4"
+  resolved "https://registry.yarnpkg.com/cross-env/-/cross-env-5.1.4.tgz#f61c14291f7cc653bb86457002ea80a04699d022"
+  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"
@@ -3470,7 +3477,7 @@ 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@^1.0.2:
+is-windows@^1.0.0, is-windows@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/is-windows/-/is-windows-1.0.2.tgz#d1850eb9791ecd18e6182ce12a30f396634bb19d"