Sandboxed JavaScript execution via QuickJS-NG.
Provides eval/2 for simple evaluation and eval/3 for evaluation
with pre-registered Elixir callback functions callable from JS.
Each runtime runs on a dedicated OS thread with configurable
memory and time limits.
Reserved JS globals
When using eval/3 in callback mode, quicksand installs four
globalThis.__quicksand_* properties on the JS runtime:
__quicksand_make_wrapper, __quicksand_dispatch,
__quicksand_cb_args, __quicksand_cb_result. User JavaScript
must not overwrite these or the callback machinery silently
breaks for that runtime. See README.md for the full list and
rationale.
Summary
Functions
Check if a runtime is alive.
Evaluate JavaScript code and return the result.
Evaluate JavaScript code with pre-registered Elixir callbacks.
Start a new JavaScript runtime on a dedicated OS thread.
Stop a runtime. Idempotent — safe to call multiple times.
Types
Functions
@spec alive?(runtime()) :: boolean()
Check if a runtime is alive.
Evaluate JavaScript code and return the result.
{:ok, 3} = Quicksand.eval(rt, "1 + 2")Evaluate JavaScript code with pre-registered Elixir callbacks.
Each callback receives its arguments as a list and must return
{:ok, value} or {:error, reason}. Errors become JS exceptions.
callbacks = %{
"add" => fn [a, b] -> {:ok, a + b} end
}
{:ok, 5} = Quicksand.eval(rt, "add(2, 3)", callbacks)Start a new JavaScript runtime on a dedicated OS thread.
Options
:timeout— max eval time in milliseconds (default30_000):memory_limit— max JS heap in bytes (default268_435_456):max_stack_size— max JS stack in bytes (default1_048_576)
@spec stop(runtime()) :: :ok
Stop a runtime. Idempotent — safe to call multiple times.