build esm module and update packages.json accordingly (#7)

Author: natterstefan

.gitignore

@@ -13,4 +13,6 @@ tmp
 # build
 dist
 es
+esm
 lib
+*.tgz

CHANGES.md

@@ -4,6 +4,12 @@ All notable changes to this project will be documented here. The format is based
 on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) and this project
 adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Added
+
+- `esm` support (build `esm` module and add id as `module` in `package.json`)
+
 ## 2019/04/06 1.0.0
 
 ### Added

babel.config.js

@@ -14,8 +14,7 @@ if (environment === 'es') {
     [
       '@babel/preset-env',
       {
-        // note: we do not build "esm" (compared with material-ui example)
-        modules: ['umd'].includes(environment) ? false : 'commonjs',
+        modules: ['esm', 'umd'].includes(environment) ? false : 'commonjs',
       },
     ],
   ]