Thank you for the example.
It gives me now an idea on how this is supposed to work.
Unfortunately I can't execute the given example because in Chrome and
IE10 this fails because of Uncaught ReferenceError: Map is not defined .
And IE10 laments about const l = data.length; Syntaxerror.
If you’re doing software development right, you’re probably doing Agile wrong.
-- Isaac Schlueter