alii/arc

⌒ JavaScript on the BEAM

Gleam

223

1,358 commits

updated Sep 21, 2026

See the code

README

[!NOTE] arc is still a young project, tread carefully!

arc ⌒

JavaScript on the BEAM

js

Arc is a JavaScript engine written in Gleam. It implements ECMAScript and has no built-in timers, I/O or concurrency. The BEAM program that embeds it provides whatever globals and host functions the JavaScript needs.

By default Arc interprets JavaScript, and it can also compile it ahead of time to Erlang. It runs on Erlang/OTP, and in the browser on AtomVM compiled to WebAssembly.

Tested against test262 on every commit:

test262 conformance chart
gleam run -- file.js       # run a script
gleam test                 # unit tests
TEST262_EXEC=1 gleam test  # full test262 suite
TEST262=1 gleam test       # parser-only test262
beam
compiler
engine
erlang
javascript

Contributors

alii

1,141 commits

alistair-bot

165 commits

aidenybai

4 commits

alii/arc

⌒ JavaScript on the BEAM

Gleam

223

1,358 commits

updated Sep 21, 2026

See the code

README

[!NOTE] arc is still a young project, tread carefully!

arc ⌒

JavaScript on the BEAM

js

Arc is a JavaScript engine written in Gleam. It implements ECMAScript and has no built-in timers, I/O or concurrency. The BEAM program that embeds it provides whatever globals and host functions the JavaScript needs.

By default Arc interprets JavaScript, and it can also compile it ahead of time to Erlang. It runs on Erlang/OTP, and in the browser on AtomVM compiled to WebAssembly.

Tested against test262 on every commit:

test262 conformance chart
gleam run -- file.js       # run a script
gleam test                 # unit tests
TEST262_EXEC=1 gleam test  # full test262 suite
TEST262=1 gleam test       # parser-only test262
beam
compiler
engine
erlang
javascript

Contributors

alii

1,141 commits

alistair-bot

165 commits

aidenybai

4 commits

Languages

Gleam

67.1%

Erlang

25.6%

JavaScript

6.2%