@liggi/logger

Minimal, zero-dep TypeScript logger with:

• Simple instance API (new Logger({ context?, enabled? }))
• Dynamic enable/disable via flags (localStorage in browser, env in Node)
• Log methods (debug|info|warn|error) and grouping
• Browser CSS labels; plain output on server

Install

Add to your workspace (publish or use via local path). Build with tsc.

Quick Start

import Logger from "@liggi/logger";

// In dev: logs are on by default.
// In prod: enable dynamically via flags.
// Browser: localStorage.LOGS_ENABLED = "true" (or DISABLE_LOGS = "true" to hard-off)
// Node:    LOGS_ENABLED=true (or DISABLE_LOGS=true)

const log = new Logger({ context: "web:testing" });
log.info("hello", { foo: 42 });
log.debug("more details");

// Instance override
const quiet = new Logger({ context: "quiet", enabled: false });
quiet.info("won't print");

ESM Only

This package is ESM-only. In CommonJS, use dynamic import:

// CommonJS example
(async () => {
  const { default: Logger } = await import('@liggi/logger');
  const log = new Logger({ context: 'web:testing' });
  log.info('hello from CJS');
})();

API

• new Logger({ context?, enabled? })
  • context: optional string label (e.g., component name)
  • enabled: optional boolean to force on/off for this instance
• Methods: debug(msg, ...args), info(msg, ...args), warn(msg, ...args), error(msg, ...args)
• group(label, fn, collapsed=true, level='info')

Dynamic Enable Flags

• Context filters (enable specific contexts):
  • Browser: set localStorage.DEBUG = "app:*,-app:noise" (or localStorage.LOGS = "...")
  • Node/SSR: set DEBUG="app:*,-app:noise" (or LOGS="...")
  • Semantics: comma/space‑separated patterns; * wildcard; - to exclude. If any includes are set, only included contexts log (minus excludes).
• Global on/off:
  • Enable globally: localStorage.LOGS_ENABLED = "true" (or LOGS_ENABLED=true in env)
  • Hard off: localStorage.DISABLE_LOGS = "true" (or DISABLE_LOGS=true)
• Default: on in non‑production (NODE_ENV !== 'production'), off in production unless enabled by flags above.

Grouping

log.group("Compute things", () => {
  log.info("step 1");
  log.warn("step 2");
}, true, "info");

Notes

• No PII redaction is performed; avoid logging secrets.

License

MIT © Jason Liggi

Scripts

• Build library: pnpm build (or yarn build / npm run build)
• Run example: pnpm run example:all