Yes, if the packages are pure JS logic (no native C++ addons, no Node-specific I/O like child_process or net). The script option auto-resolves imports from node_modules/ and bundles via OXC. Node compat APIs (process, path, fs, os, Buffer) are available with apis: [:browser, :node]. For packages with native .node addons, there's load_addon/3 which supports N-API.
— Memory limits: JS_SetMemoryLimit per-runtime (256 MB default), JS_SetContextMemoryLimit per-context. Exceeding → JS exception, not a crash.
— Execution limits: interrupt handler checks a nanosecond deadline every opcode. For contexts, max_reductions caps JS operations independently of wall-clock time.
— API surface: apis: false gives bare QuickJS — no fetch, no fs, no DOM, no I/O. You control exactly which Elixir functions JS can call via the handlers map. JS cannot call arbitrary Elixir code.
— Conversion limits: max_convert_depth (32) and max_convert_nodes (10k) prevent pathological objects from blowing up during JS↔BEAM conversion.
— Process isolation: separate OS thread, separate QuickJS heap per runtime.
No seccomp — QuickJS runs in-process so seccomp would restrict the entire BEAM. The sandbox boundary is QuickJS-NG's memory-safe interpreter (no JIT, no raw pointer access from JS) plus the API surface control above.
1. Yes. Each runtime is a GenServer (= own process + mailbox). There's also a lighter-weight Context mode where many JS contexts share one OS thread via a ContextPool, but each context still maps 1:1 to a BEAM process.
2. No. JS runs on a dedicated OS thread, outside the BEAM scheduler. But there's an interrupt handler (JS_SetInterruptHandler) that checks a deadline on every JS opcode boundary — pass timeout: 1000 to eval and it interrupts after 1s, runtime stays usable. For contexts there's also max_reductions — QuickJS-NG counts JS operations and interrupts when the budget runs out, closest analog to BEAM reductions.
3. QuickJS-NG uses refcounting with cycle detection. Each runtime/context has its own GC — one collecting doesn't touch another. When a Runtime GenServer terminates, JS_FreeContext + JS_FreeRuntime release everything.
4. No, standard JS mutability. But the JS↔Erlang boundary copies values — no shared mutable state across that boundary.
5. QuickJS-NG enforces JS_SetMemoryLimit per-runtime (default 256 MB) and JS_SetContextMemoryLimit per-context. Exceeding the limit raises a JS exception, not a segfault. It propagates as {:error, ...} to the caller. Since each runtime is a supervised GenServer, the supervisor restarts it. There are tests for OOM in one context not crashing the pool, and one runtime crashing not affecting siblings.
So if you map your design tokens to Figma variables first, components will reference them. Parsing CSS/Tailwind configs automatically could be a good feature though.
I still have a lot of assets living in Figma, and for some things it’s simply faster to prototype there before moving to code.
Personally, I’d really like to automate part of the workflow around exporting from Figma and assembling a design system into components — right now there’s just too much manual work involved.
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