process

Note

To enable built-in Node.js APIs and polyfills, add the nodejs_compat compatibility flag to your Wrangler configuration file. This also enables nodejs_compat_v2 as long as your compatibility date is 2024-09-23 or later. Learn more about the Node.js compatibility flag and v2.

The process ↗ module in Node.js provides a number of useful APIs related to the current process.

Initially Workers only supported nextTick, env, exit, getBuiltinModule, platform and features on process, which was then updated with the enable_nodejs_process_v2 flag to include most Node.js process features.

Refer to the Node.js documentation for process ↗ for more information.

Workers-specific implementation details apply when adapting Node.js process support for a serverless environment, which are described in more detail below.

process.env

In the Node.js implementation of process.env, the env object is a copy of the environment variables at the time the process was started. In the Workers implementation, there is no process-level environment, so by default env is an empty object. You can still set and get values from env, and those will be globally persistent for all Workers running in the same isolate and context (for example, the same Workers entry point).

When Node.js compatibility is turned on and the nodejs_compat_populate_process_env compatibility flag is set, process.env will contain any environment variables, secrets, or version metadata metadata that has been configured on your Worker.

Relationship to per-request env argument in fetch() handlers

Workers have a concept of environment variables that are applied on a per-Worker and per-request basis.

By default, these are not accessible via the process.env API. To automatically populate environment variables and secrets on process.env, enable the nodejs_compat_populate_process_env compatibility flag and disable the disallow_importable_env compatibility flag. It is also possible to manually copy these values into process.env if necessary -- but only within the context of a request.

Setting any value on process.env will coerce that value into a string.

JavaScript

import * as process from "node:process";

export default {
  fetch(req, env) {
    // Set process.env.FOO to the value of env.FOO if process.env.FOO is not already set
    // and env.FOO is a string.
    process.env.FOO ??= (() => {
      if (typeof env.FOO === "string") {
        return env.FOO;
      }
    })();
  },
};

It is strongly recommended that you do not replace the entire process.env object with the cloudflare env object. Doing so will cause you to lose any environment variables that were set previously and will cause unexpected behavior for other Workers running in the same isolate. Specifically, it would cause inconsistency with the process.env object when accessed via named imports.

JavaScript

import * as process from 'node:process';
import { env } from 'node:process';

process.env === env; // true! they are the same object
process.env = {}; // replace the object! Do not do this!
process.env === env; // false! they are no longer the same object

// From this point forward, any changes to process.env will not be reflected in env,
// and vice versa!

## `process.nextTick()`

The Workers implementation of `process.nextTick()` is a wrapper for the standard Web Platform API [`queueMicrotask()`](https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/queueMicrotask).

```js
import { env, nextTick } from "node:process";

env["FOO"] = "bar";
console.log(env["FOO"]); // Prints: bar

nextTick(() => {
  console.log("next tick");
});

Stdio

process.stdout ↗, process.stderr ↗ and process.stdin ↗ are supported as streams. stdin is treated as an empty readable stream. stdout and stderr are non-TTY writable streams, which output to normal logging output only with stdout: and stderr: prefixing.

The line buffer works by storing writes to stdout or stderr until either a newline character \n is encountered or until the next microtask, when the log is then flushed to the output.

This ensures compatibility with inspector and structured logging outputs.

Current Working Directory

process.cwd() ↗ is the current workding directory, used as the default path for all filesystem operations, and is initialized to /bundle.

process.chdir() ↗ allows modifying the cwd and is respected by FS operations when using enable_nodejs_fs_module.

Hrtime

While process.hrtime ↗ high-resolution timer is available, it provides an inaccurate timer for compatibility only.

Unsupported Features

The following process properties are currently entirely unsupported and return undefined: binding, channel, connected, debugPort, dlopen, exitCode, finalization, getActiveResourcesInfo, hasUncaughtExceptionCaptureCallback, kill, memoryUsage, noDeprecation, permission, ref, release, report, resourceUsage, send, setUncaughtExceptionCaptureCallback, sourceMapsEnabled, threadCpuUsage, throwDeprecation, traceDeprecation, unref.

These unimplemented features may be feature-detected via conditional gating patterns like:

JavaScript

if (process.dlopen) {
  // use dlopen when available
}