chore: fix npm build scripts on windows

Author: alisd23

modules/TransitionUtils.js

@@ -12,22 +12,20 @@ const enterHooks = new PendingHooks()
 const changeHooks = new PendingHooks()
 
 function createTransitionHook(hook, route, asyncArity, pendingHooks) {
+  const isSync = hook.length < asyncArity
+
   const transitionHook = (...args) => {
     hook.apply(route, args)
 
-    if (hook.length < asyncArity) {
+    if (isSync) {
       let callback = args[args.length - 1]
-      // Add synchronous hook to pendingHooks (gets removed instantly later)
-      pendingHooks.add(transitionHook)
       // Assume hook executes synchronously and
       // automatically call the callback.
       callback()
     }
   }
 
-  if (hook.length >= asyncArity) {
-    pendingHooks.add(transitionHook)
-  }
+  pendingHooks.add(transitionHook)
 
   return transitionHook
 }

package.json

@@ -16,8 +16,8 @@
   "bugs": "https://github.com/ReactTraining/react-router/issues",
   "scripts": {
     "build": "npm run build-cjs && npm run build-es",
-    "build-cjs": "rimraf lib && cross-env BABEL_ENV=cjs babel ./modules -d lib --ignore '__tests__'",
-    "build-es": "rimraf es && cross-env BABEL_ENV=es babel ./modules -d es --ignore '__tests__'",
+    "build-cjs": "rimraf lib && cross-env BABEL_ENV=cjs babel ./modules -d lib --ignore __tests__",
+    "build-es": "rimraf es && cross-env BABEL_ENV=es babel ./modules -d es --ignore __tests__",
     "build-umd": "cross-env NODE_ENV=development webpack modules/index.js umd/ReactRouter.js",
     "build-min": "cross-env NODE_ENV=production webpack -p modules/index.js umd/ReactRouter.min.js",
     "lint": "eslint examples modules scripts tools *.js",