Basic flow configuration

.flowconfig

@@ -0,0 +1,8 @@
+[ignore]
+.*/node_modules/*
+
+[include]
+
+[libs]
+
+[options]

package.json

@@ -10,15 +10,18 @@
     "babel-cli": "^6.22.2",
     "babel-core": "^6.22.1",
     "babel-loader": "^6.2.10",
+    "babel-plugin-transform-flow-strip-types": "^6.22.0",
     "babel-preset-es2015": "^6.22.0",
     "babel-preset-react": "^6.22.0",
+    "flow-bin": "^0.38.0",
     "react": "^15.4.2",
     "react-dom": "^15.4.2",
     "webpack": "2",
     "webpack-dev-server": "2"
   },
   "scripts": {
     "start": "node_modules/.bin/webpack-dev-server --open",
-    "build": "node_modules/.bin/webpack --config webpack.config.js"
+    "build": "node_modules/.bin/webpack --config webpack.config.js",
+    "flow": "flow; test $? -eq 0 -o $? -eq 2"
   }
 }

src/App.js

@@ -1,7 +1,12 @@
+//@flow
 import React from 'react';
 import ReactDOM from 'react-dom';
 
+function world(): string {
+  return "world"
+}
+
 ReactDOM.render(
-  <h1>Hello, world!</h1>,
+  <h1>Hello {world()}</h1>,
   document.getElementById('root')
 );

webpack.config.js

@@ -13,7 +13,8 @@ const config = {
         test: /\.(js|jsx)$/,
         loader: 'babel-loader',
         options: {
-          presets: ["es2015", "react"]
+          presets: ["es2015", "react"],
+          plugins: ["transform-flow-strip-types"]
         },
         exclude: [/node_modules/]
       }

yarn.lock

@@ -1275,6 +1275,10 @@ find-up@^1.0.0:
     path-exists "^2.0.0"
     pinkie-promise "^2.0.0"
 
+flow-bin@^0.38.0:
+  version "0.38.0"
+  resolved "https://registry.yarnpkg.com/flow-bin/-/flow-bin-0.38.0.tgz#3ae096d401c969cc8b5798253fb82381e2d0237a"
+
 for-in@^0.1.5:
   version "0.1.6"
   resolved "https://registry.yarnpkg.com/for-in/-/for-in-0.1.6.tgz#c9f96e89bfad18a545af5ec3ed352a1d9e5b4dc8"