When using compatibility mode there are a few things happening behind the scenes:

• Node globals are available in the global scope, so you can access process, global, Buffer, setImmediate, clearImmediate. This is done by executing on startup.

• • import fs from "fs";
  • import fs from "node:fs";
  • const fs = require("fs");
  • const fs = require("node:fs");

• Deno will support Node resolution algorithm so importing packages using “bare” specifiers will work. For details on how module resolution works check Node documentation on CJS and modules.

Following built-in Node modules are currently supported:

• assert (partly)
• assert/strict (partly)
• buffer
• console (partly)
• child_process (partly)
• dns (partly)
• events
• fs (partly)
• fs/promises (partly)
• http (partly)
• module
• net (partly)
• os (partly)
• path
• perf_hooks (partly)
• process (partly)
• querystring
• readline (partly)
• sys (partly)
• timers
• timers/promises
• tty (partly)
• url (partly)
• util (partly)
• worker_threads

Following modules are not yet implemented:

• cluster
• dgram
• http2
• https
• repl
• tls
• zlib

TypeScript support

Currently, the compability mode does not support TypeScript.

In the upcoming releases we plan to add support for a types field in , to automatically lookup types and use them during type checking.

In the long term, we’d like to provide ability to consume TypeScript code authored for the Node.js runtime.