A vm library built on top of Deno's worker.

Usage

import { VM } from "https://deno.land/x/worker_vm@v0.1.1/mod.ts";

const vm = new VM({
  timeoutMs: 30 * 1000,
  permissions: "none",
}); // create a new VM Worker

console.log(await vm.run("1 + 1")); // run code in the worker

await vm.run(`
function sum(a, b) {
  return a + b;
} `); // define a function

console.log(await vm.call("sum", 2, 3)); // 5

vm.close(); // terminate the worker

CLI permissions

• --unstable-worker-options - permission options in worker is an unstable feature.
• --allow-read=path/to/worker.ts - to launch the worker.

Common issues

The code may terminate the worker

Although Deno is able to block disk/network access by default, we can't prevent the code from calling self.close(). If this happens, the worker will be terminated. All calls to vm.run will timeout.

XXX is not cloneable

Data must be cloneable to be passed to the worker:

• VM.call - function arguments are JSON-cloned.
• The result of VM.run - throws an error if it is not cloneable.
• VM.on("console") - function arguments are JSON-cloned.

Requires net/read/write/... access to

Grant specific permissions to worker-vm by creating new VM with permissions: option:

const vm = new VM({
  // https://docs.deno.com/api/web/~/WorkerOptions.deno#property_permissions
  permissions: // ...
});

For contributors

Testing

NOTE: NotCapable error not found.

According to Deno documentation Deno.errors.NotCapable: "Before Deno 2.0, this condition was covered by the PermissionDenied error."

Install deno version 2.0 or later should resolve the issue.

Update Deno built-in types

Similar projects

• vm2 - discontinued.
• isolated-vm - a much more powerful vm that runs in node. However, it has to be built from source when installing.

Changelog

• 0.2.1 (Feb 7, 2025)

  • Add: permissions option.

• 0.2.0 (Oct 10, 2023)

  • Add: capture console output.

• 0.1.2 (Oct 10, 2023)

  • Update README.

• 0.1.0 (Oct 9, 2023)

  • Initial release.