Support dart2wasm

[leecommamichael]

To reproduce:

• have the dart2wasm compiler
• import this package into a main.dart with void main
• run dart compile wasm main.dart Output:

../../../AppData/Local/Pub/Cache/hosted/pub.dev/pointycastle-3.7.4/lib/src/platform_check/node_crypto.dart:5:1: Error: JS interop library 'package:js/js.dart' can't be imported when compiling to Wasm. Try using 'dart:js_interop' or 'dart:js_interop_unsafe' instead. import 'package:js/js.dart'; ^ ../../../AppData/Local/Pub/Cache/hosted/pub.dev/pointycastle-3.7.4/lib/src/platform_check/web.dart:5:1: Error: JS interop library 'package:js/js.dart' can't be imported when compiling to Wasm. Try using 'dart:js_interop' or 'dart:js_interop_unsafe' instead. import 'package:js/js.dart'; ^

This library impacts the popular package:image. I've filed a matching report with them here.

[The-RootCause]

Definitely needed since the package is used in many known packages making them unusable with Wasm. Thank you

[konsultaner]

I started porting my code to the web package to support wasm. It was quite hard to get into it, but finally got it. I might be able to help here.

I only saw 2 files where actual web code was written. Is that right? I could exchange the old package:js with package:web. That package:web is fully compatible with the dart2wasm compiler.

[konsultaner]

Dart fixed the blocking issue. If someone would take a look at my PR, this issue could be closed 😇

[konsultaner]

@leecommamichael this issue is fixed. You might want to close this issue.

[Ephenodrom]

Close as the PR is merged and live on pub.dev.

[sgehrman]

doesn't work, you are includeing teh js package.

dart:js_interop, which replaces package:js and dart:js

[konsultaner]

Where is it used? Im using pc-dart in my package and it compiles to wasm.