Evaluating JavaScript

Deno Sandbox provides a sandboxed Linux microVM. This is useful for evaluating code that is not trusted or for testing code that is not safe to run in your main runtime.

You can evaluate JavaScript code in a sandbox using the eval function.

import { Sandbox } from "@deno/sandbox";

await using sandbox = await Sandbox.create();

const result = await sandbox.deno.eval(`
  const a = 1;
  const b = 2;
  a + b;
`);
console.log("result:", result);

Calling sandbox.deno.eval() lets you run arbitrary JavaScript snippets directly inside the sandbox’s Deno runtime without writing files or shelling out. This is useful when you want to prototype logic, run small computations, or inspect the sandbox environment itself quickly. Use it for dynamic scripts or exploratory debugging where creating a full module would be overkill.

For more information, see the Deno Sandbox documentation.