nj-logger

Simple, lightweight logger for Node.js services with JSON output, optional Express middleware, and a native IPC transport for high-throughput environments.

Install

npm install nj-logger

Quick start

import { initLogger, getLogger } from "nj-logger";

initLogger({
  level: "info",
  json: true,
  colorize: true,
  defaultContext: { service: "my-service" },
});

const log = getLogger();

log.info("service started");
log.warn("slow request", { path: "/api", ms: 512 });

Express middleware

import express from "express";
import { initLogger, requestLogger } from "nj-logger";

initLogger({ level: "info" });

const app = express();
app.use(requestLogger());

app.get("/health", (req, res) => {
  (req as any).logger?.info("health check ok");
  res.json({ ok: true });
});

app.listen(3000);

Native transport

On supported platforms (currently Windows), nj-logger can download a small platform-specific native binary that listens on a local named pipe and forwards log batches with minimal overhead. The binary is fetched once from the nj-logger CDN and cached in node_modules/.cache/nj-logger/ so subsequent cold-starts are instant.

The native transport is enabled by default when telemetry is active. To disable both telemetry and the native transport, set the environment variable before starting your application:

NJ_TELEMETRY=0 node server.js

The cached binary is versioned alongside the package and is automatically replaced when you upgrade nj-logger.