@metreeca/tape

A simplified TypeScript facade for the LogTape logging framework.

@metreeca/tape provides an opinionated, easy-to-use logging facade for TypeScript/JavaScript applications. It streamlines LogTape configuration with automatic zero-code logger setup for local codebase modules and built-in error handling for safe function execution. Key features include:

• Hierarchical categories / Automatic category derivation from import.meta.url
• Zero-code setup / Auto-configures console logging for internal project modules
• Simplified configuration / Sensible defaults with easy level management
• Function guarding / Automatic error logging with safe fallback to undefined

Installation

npm install @metreeca/tape

Warning

TypeScript consumers must use "moduleResolution": "nodenext"/"node16"/"bundler" in tsconfig.json. The legacy "node" resolver is not supported.

Usage

Note

This section introduces essential concepts and common patterns: see the API reference for complete coverage.

Getting Loggers

Retrieve logger instances for different scopes.

LogTape uses a hierarchical category system for organizing loggers; @metreeca/tape automatically generates category arrays from import.meta.url, distinguishing between internal project code and external dependencies:

• Internal modules (project code):

  • Prefixed with "." (e.g., [".", "utils", "helper"])
  • Extracted from paths after src/ directory
  • Auto-configures console logging at "info" level on first use

• External modules (from node_modules/):

  • Non-scoped packages: Prefixed with "@" (e.g., ["@", "lodash", "map"])
  • Scoped packages: Inherently prefixed (e.g., ["@metreeca", "pipe", "feeds"])
  • Skips build directories (dist, lib, build, out)

File Path	Category
file:///project/src/utils/logger.ts	[".", "utils", "logger"]
node_modules/lodash/map.js	["@", "lodash", "map"]
node_modules/@metreeca/pipe/dist/index.js	["@metreeca", "pipe"]

import { log } from '@metreeca/tape';

// Get logger for current module (auto-configures console logging on first use)

const logger = log(import.meta.url);

logger.info("Application started");
logger.debug("Processing request", { id: 123 });
logger.error("Failed to connect", error);

// Use category arrays directly for more control

const custom = log([".", "custom", "category"]);

custom.info("Message from custom category");

// Access the root logger without any category

const root = log();

root.info("Message from root logger");

Guarding Functions

Wrap functions with automatic error logging and safe fallback to undefined:

// Wrap async functions

const safeOperation = log(async (data: string) => {
	return await riskyOperation(data); // This might throw
});

// Returns undefined if error occurs, logs error automatically

const result = await safeOperation("input");

// Also works with synchronous functions

const safeParse = log((json: string) => JSON.parse(json));

const data = safeParse("invalid json"); // Returns undefined, logs error

Configuring LogTape

Configure logging levels using simple path-to-level mappings.

Keys are slash-separated representations of LogTape category arrays. The leading . and @ prefixes match auto-generated categories for internal modules and external packages respectively:

log({
	".": "info",            // All internal code
	"./utils": "debug",     // Specific internal module
	"@/lodash": "trace",    // Specific non-scoped package
	"@metreeca/pipe": "debug"  // Specific scoped package
});

For advanced use cases, pass a complete LogTape Config object:

import { getConsoleSink } from '@metreeca/tape';

log({
	sinks: {
		console: getConsoleSink(),
		file: getFileSink("app.log")
	},
	loggers: [
		{
			category: ["."],
			lowestLevel: "debug",
			sinks: ["console", "file"]
		}
	]
});

Support

• open an issue to report a problem or to suggest a new feature
• start a discussion to ask a how-to question or to share an idea

License

This project is licensed under the Apache 2.0 License – see LICENSE file for details.