Skip to main content

Evaluating JavaScript

Edit on Github

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

Import the Deno Sandbox SDK
import { Sandbox } from "jsr:@deno/sandbox";
Create a sandbox
await using sandbox = await Sandbox.create();
Run JS in the sandbox with eval
const result = await sandbox.deno.eval(`
  const a = 1;
  const b = 2;
  a + b;
  `);
console.log("result:", result);

Run this example locally using the Deno CLI:

deno run -A https://docs.deno.com/examples/scripts/sandbox_evaluating_javascript.ts

Additional resources

Did you find what you needed?

Privacy policy