Dart is quite similar to Java. If you are already familiar with Java I believe it will take you very little time to get started with Dart.

FWIW, I was able to write two small but useful program in Dart in one day, without any experience with the language at all:

- A script to convert CSV file to SELECT ... UNION ALL SELECT ... statements

- A script to parse my timesheet (in Emacs' org-mode) & insert it into my client's timesheet database

I just used these 3 resources:

[1] Dart language tour https://www.dartlang.org/guides/language

[2] Standard library introduction https://www.dartlang.org/guides/libraries

[3] Standard library reference (like JavaDocs) https://api.dartlang.org/stable/1.24.2/index.html

[4] And the pub package manager https://www.dartlang.org/tools/pub

It's really easy to get started with almost any language, the problem is becoming an expert in it. How can somebody become an expert on the nuances of JS, Typescript, Dart, etc not to mention libraries and APIs of each? And that's just for the frontend.

Polymer with native iOS/Android support would be… Not Polymer.

Polymer is a thin layer of sugar on top of the web platform, it's 100% web, it doesn't make sense outside of the browser because it doesn't have its own special component model, it literally just directly subclasses HTMLElement to provide sugar, that's it.

> Dart? [...] JS fatigue

I think you might like working with Dart. The entire ecosystem is standardized. And if you do Flutter stuff, Flutter is the only framework.

Learning the language isn't a big deal. You already know most of the syntax and its semantics are straightforward.

You can try doing some Hello World stuff over at DartPad:

https://dartpad.dartlang.org/

Google IO sessions sometimes feel a bit schizophrenic, if you watch all tracks, you will see Android, Web and Flutter teams kind of taking jabs at each other about the right way of doing apps.

I love Polymer too, but if you are like me the parts you like most about Polymer are the beautiful widgets and the ability to create new widgets. Flutter provides that for mobile apps. As someone else said, Polymer itself is just a web implementation of user-defined HTML elements and makes no sense for mobile apps.

As for not wanting to learn Dart, if you are currently developing mobile apps for one platform (say Android) and you want to port your apps to the other platform (say iOS) then unless you already know the languages and libraries used by that other platform (say Swift or Objective-C) then you already have to learn a new language. Wouldn't it be better to learn something like Dart that compiles natively on both platforms? Then you can just write one program. In particular, maintenance is much easier.

(disclaimer, I like Flutter so much I just joined the Flutter team)

Dart is Java/C# like - you will be fluent in one day

I understand where you are coming from - however, Dart is super easy to start using, you will feel at home in no time. Solid, though-out standard library, everything just works out of the box. Honestly, it's a very refreshing experience compared to JS / TypeScript. I bet you'll love it after a day or two.

I think learning a new language is more acceptable when you're also using it on a new platform. I was sceptical about picking up Swift, but I was up and running within a few hours.

> On top of Elixir, Go, and JS fatigue, I don't think I have any more room left for another language to "try".

Not to mention Elm.