Use global React in UMD build

Author: mjackson

scripts/release.js

@@ -19,7 +19,7 @@ if (process.cwd() !== resolvePath(__dirname, '..')) {
 // is a "pre-release" if nextVersion is premajor, preminor,
 // prepatch, or prerelease
 const nextVersion = prompt(`Next version (current version is ${getPackageVersion()})? `)
-const isPrerelease = nextVersion.substring(0, 3) === 'pre' || nextVersion.indexOf('-') !== -1
+const isPrerelease = nextVersion.substr(0, 3) === 'pre' || nextVersion.indexOf('-') !== -1
 
 // 1) Make sure the tests pass
 exec('npm test -- --single-run')

webpack.config.js

@@ -1,12 +1,20 @@
 const webpack = require('webpack')
 
 module.exports = {
-
   output: {
     library: 'ReactRouter',
     libraryTarget: 'umd'
   },
 
+  externals: {
+    react: {
+      root: 'React',
+      commonjs2: 'react',
+      commonjs: 'react',
+      amd: 'react'
+    }
+  },
+
   module: {
     loaders: [
       { test: /\.js$/, exclude: /node_modules/, loader: 'babel' }
@@ -18,5 +26,4 @@ module.exports = {
       'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV || 'development')
     })
   ]
-
 }