missionlog

missionlog

🚀 missionlog is a lightweight, structured logging library designed for performance, flexibility, and ease of use.
It works as a drop-in replacement for console.log or ts-log, featuring tag-based organization, log level filtering, and customizable output handling—all in a tiny (~1KB) package.

✔ Fully Typed (TypeScript) • ✔ ESM & CJS Support • ✔ Zero Dependencies

✨ Why Use missionlog?

Compared to other logging libraries like ts-log, missionlog offers:

✅ Drop-in Replacement for console.log & ts-log – Start using it instantly.
✅ Seamless Upgrade to Tag-Based Logging – Reduce log clutter by dynamically focusing on what's important.
✅ Configurable Log Levels – Adjust visibility for each tag at runtime to filter noise.
✅ Customizable Output – Send logs anywhere: console, JSON, cloud services.
✅ Blazing Fast Performance – O(1) log level lookups for minimal overhead.
✅ TypeScript-First – Full type safety, no need for @types.
✅ Works Everywhere – Browser, Node.js, Firebase, AWS Lambda etc.

📦 Installation

npm i missionlog  

yarn add missionlog  

🎯 Focus on What Matters, When It Matters

missionlog lets you filter logs dynamically to avoid clutter and focus on what's important—without forcing you to use tags.

🚀 Example

import { DEFAULT_TAG, log, LogLevel, LogLevelStr, tag } from "missionlog";
import chalk from "chalk";

// Use the built-in dummy logger so becomes a no-op
log.info(tag.engineering, "Engaging warp drive! Destination: The Final Frontier.");

// Let's set some tags
log.init({ Engineering: LogLevel.INFO, Transporter: LogLevel.DEBUG });

// Log with a tag
log.info(tag.Engineering, "Warp Factor 9!");

// Override the built-in dummy with custom behavior
log.init({ Engineering: LogLevel.INFO }, createLogHandler());

// Engineering's level is INFO+ so this gets logged!
log.info(tag.Engineering, "Warp Factor 5.");

// No tag so works like console and uses the default level
log.error("Alert! Evil twin detected!");

// Gets filtered since Engineering is INFO+
log.debug(tag.Engineering, "Warp Factor 9!");

// Update tag levels and override default (INFO)
log.init({
  Engineering: LogLevel.TRACE,
  [DEFAULT_TAG]: LogLevel.ERROR,
  Transporter: LogLevel.DEBUG,
});

// Log an error
const error = new Error("Warp core breach!");
log.error(tag.Engineering, "🚨 Red Alert!", error.message);

// Show some color!
log.debug(tag.Transporter, "✨ Beam me up, Scotty!");

// Log objects properly
log.warn(tag.Transporter, "Transporter anomaly detected,", { evilTwin: true });

// Replace dummy logger with custom behavior
function createLogHandler() {
  const logConfig: Record<
    LogLevelStr,
    { color: (text: string) => string; method: (...args: unknown[]) => void }
  > = {
    ERROR: { color: chalk.red, method: console.error },
    WARN: { color: chalk.yellow, method: console.warn },
    INFO: { color: chalk.green, method: console.log },
    DEBUG: { color: chalk.magenta, method: console.log },
    TRACE: { color: chalk.cyan, method: console.log },
    OFF: { color: () => '', method: () => {} }, // No-op
  };

  return (level: LogLevelStr, tag: string, message: unknown, params: unknown[]) => {
    const { method, color } = logConfig[level];  
    const logLine = `[${color(level)}] ${tag ? tag + ' - ' : ''}${message}`;
    method(logLine, ...params);
  };
}

📄 License

MIT License
© 2019-2025 Ray Martone

🚀 Install missionlog today and make logging clean, structured, and powerful!