@agentine/beacon

Drop-in replacement for debug. Namespace-based debug logging for Node.js and browsers with zero dependencies.

Install

npm install @agentine/beacon

Usage

const beacon = require('@agentine/beacon');
const log = beacon('app:server');

log('listening on port %d', 3000);
// app:server listening on port 3000 +0ms

ESM:

import beacon from '@agentine/beacon';
const log = beacon('app:server');

Enabling namespaces

Set the DEBUG environment variable:

DEBUG=app:* node app.js        # enable all app:* namespaces
DEBUG=app:server node app.js   # enable only app:server
DEBUG=*,-app:db node app.js    # enable all except app:db
DEBUG=app,db node app.js       # enable app and db

In the browser, use localStorage:

localStorage.debug = 'app:*';

API

beacon(namespace)

Create a debug function for the given namespace.

const debug = beacon('myapp:server');
debug('listening');        // only outputs if 'myapp:server' is enabled

beacon.enable(namespaces)

Enable debug output for the given namespace string.

beacon.enable('app:*');
beacon.enable('app:server,app:db');
beacon.enable('*,-app:secret');

beacon.disable()

Disable all namespaces. Returns the previously enabled namespaces string.

const prev = beacon.disable();

beacon.enabled(namespace)

Check if a namespace is enabled.

if (beacon.enabled('app:server')) {
  // ...
}

debug.extend(sub, [delimiter])

Create a sub-namespace.

const debug = beacon('app');
const server = debug.extend('server');  // app:server
const api = debug.extend('api', '/');   // app/api

debug.destroy()

Remove the debugger instance.

Format specifiers

• %s — String
• %d — Number
• %o — Object (compact)
• %O — Object (full)
• %j — JSON (browser only)
• %% — Literal %

Custom formatters

beacon.formatters.h = (v) => v.toString('hex');

const debug = beacon('app');
debug('buffer: %h', Buffer.from([0xde, 0xad]));
// app buffer: dead +0ms

beacon.humanize

Access the built-in ms parser/formatter:

beacon.humanize('1h');      // 3600000
beacon.humanize(60000);     // '1m'

Migrating from debug

Replace the package name in your imports:

- const debug = require('debug');
+ const debug = require('@agentine/beacon');

Or with ESM:

- import debug from 'debug';
+ import debug from '@agentine/beacon';

Everything else works the same — namespaces, environment variables, wildcards, formatters, and the full API are compatible with debug@4.x.

Environment variables

Variable	Description
DEBUG	Comma/space-separated namespace patterns to enable
DEBUG_COLORS	Force enable/disable colors (true/false)
DEBUG_HIDE_DATE	Hide ISO date prefix in non-color mode (true/false)

Features

• Full debug@4.x API compatibility
• Zero dependencies (ms parsing is inlined)
• CJS + ESM dual module
• TypeScript type definitions included
• Node.js: stderr output with 256-color support
• Browser: console output with CSS colors
• Automatic color assignment per namespace
• Time deltas between log calls

License

MIT