Cleanup Build Chain (#48)

* condense rollup:* scripts; set multiple targets

* add module entry

* remove mkdirp

Author: lukeed

package.json

@@ -1,20 +1,19 @@
 {
   "name": "mitt",
-  "amdName": "mitt",
   "version": "1.1.0",
   "description": "Tiny 200b functional Event Emitter / pubsub.",
   "jsnext:main": "src/index.js",
+  "module": "dist/mitt.es.js",
   "main": "dist/mitt.js",
   "umd:main": "dist/mitt.umd.js",
   "scripts": {
     "bump": "standard-version",
     "testonly": "mocha --compilers js:babel-register test/**/*.js",
     "lint": "eslint src test",
     "test": "flow && npm run lint && npm run testonly",
-    "build": "npm-run-all clean -p rollup:* -p minify:* -s docs size",
-    "clean": "rimraf dist && mkdirp dist",
-    "rollup:cjs": "rollup -c rollup.config.js -m -f cjs -n $npm_package_amdName $npm_package_jsnext_main -o $npm_package_main",
-    "rollup:umd": "rollup -c rollup.config.js -m -f umd -n $npm_package_amdName $npm_package_jsnext_main -o $npm_package_umd_main",
+    "build": "npm-run-all clean -p rollup -p minify:* -s docs size",
+    "clean": "rimraf dist",
+    "rollup": "rollup -c",
     "minify:cjs": "uglifyjs $npm_package_main -cm toplevel -o $npm_package_main -p relative --in-source-map ${npm_package_main}.map --source-map ${npm_package_main}.map",
     "minify:umd": "uglifyjs $npm_package_umd_main -cm -o $npm_package_umd_main -p relative --in-source-map ${npm_package_umd_main}.map --source-map ${npm_package_umd_main}.map",
     "docs": "documentation readme src/index.js --section API -q",
@@ -68,7 +67,6 @@
     "eslint": "^3.13.1",
     "flow-bin": "^0.38.0",
     "gzip-size-cli": "^1.0.0",
-    "mkdirp": "^0.5.1",
     "mocha": "^3.2.0",
     "npm-run-all": "^2.1.1",
     "pretty-bytes-cli": "^2.0.0",

rollup.config.js

@@ -1,10 +1,19 @@
 import buble from 'rollup-plugin-buble';
 import flow from 'rollup-plugin-flow';
 
+const pkg = require('./package');
+
 export default {
+	entry: 'src/index.js',
 	useStrict: false,
+	sourceMap: true,
 	plugins: [
-    flow(),
+		flow(),
 		buble()
+	],
+	targets: [
+		{dest: pkg.main, format: 'cjs'},
+		{dest: pkg.module, format: 'es'},
+		{dest: pkg['umd:main'], format: 'umd', moduleName: pkg.name}
 	]
 };