Publish Library as ES Module

Is your feature request related to a problem? Please describe.

Consuming the library in modern web frameworks is problematic. For example using it in Angular causes the build optimization to bail out.

Describe the solution you'd like

Correct me if I am wrong but you already use ECMAScript style imports and exports. The problem is, that your only output inside the RollUp config is umd. It should be as simple as adding another output with the es output format and specifying it in package.json's exports property.