Loggette

A lightweight, zero-dependency TypeScript logger with template literal support, color output, and runtime level control.

Features

• Template literal API for easy value interpolation
• Four log levels: error, warn, info, debug
• Automatic color detection (TTY, NO_COLOR, FORCE_COLOR)
• Runtime level and color switching
• Swappable default logger
• Chainable methods

Installation

Depending on your package manager:

• npm i loggette
• bun add loggette
• yarn add loggette
• pnpm add loggette
• deno add npm:loggette

Usage

Default logger

import logger from "loggette";

logger.info`Server started on port ${port}`
.warn(`Config file ${"config.json"} not found, using defaults`)
.error`Failed to connect to database: ${err.message}`
.debug`Parsed payload: ${JSON.stringify(payload)}`;

Custom logger

import { createLogger } from "loggette";

const logger = createLogger("debug");

logger.debug`This will show`;

Chaining

All methods return the logger instance, so they can be chained:

const logger = createLogger("info")
    .setLevel("debug")
    .setUseColor(false)
    .setDefault()
    .debug("test") // not printed
    .info`Logged in as ${username}`;

Template literals

Interpolated values are highlighted in the level's color:

logger.info`Connected to ${"localhost"}:${5432}`;
// the values "localhost" and "5432" are colored
logger.info(`Database ${db.name} connected.`)
// db.name is not highlighted

[!NOTE] Interpolated values are only processed using String() so data types like objects may print as "[object, Object]". Validate the values yourself as this is only a minimal logger.

Log Levels

Levels are ordered by severity. Setting a level suppresses everything below it.

| Level | Prints | |---------|-------------------------------| | error | errors only | | warn | errors, warnings | | info | errors, warnings, info | | debug | everything |

const logger = createLogger("warn");

logger.info`This won't print`;
logger.warn`This will`;

API

createLogger(level, useColor?)

Creates a new logger instance.

| Param | Type | Description | |------------|------------|--------------------------------------------------| | level | LogLevel | Minimum level to print | | useColor | boolean? | Force color on/off. Auto-detects if not provided |

logger.setLevel(level)

Change the log level at runtime. Returns the logger for chaining.

logger.setLevel("debug");

logger.setUseColor(color?)

Force color on/off, or pass undefined to re-enable auto-detection. Returns the logger for chaining.

logger.setUseColor(false); // force off
logger.setUseColor();      // back to auto

logger.setDefault()

Replace the module-level default logger with this instance. Returns the logger for chaining.

const logger = createLogger("debug");
logger.setDefault();

Color Control

Loggette respects standard color environment variables:

| Variable | Effect | |---------------|-------------------------------| | NO_COLOR | Disables color (any value) | | FORCE_COLOR=0 | Disables color | | FORCE_COLOR=1 | Enables color | | TTY detection | Enables color if stdout is a TTY |

Output Format

2026-06-23T10:00:00.000Z LEVEL : MESSAGE WITH HIGHLIGHTS

• Timestamp in dim gray
• Level in its respective color, padded to 5 chars
• Interpolated values highlighted in level color