@very-coffee/hello

A type-safe utility for creating structured logging across multiple namespaces and environments in TypeScript applications.

Features

• Type-safe logging with namespace and environment level support
• DEBUG environment variable support (similar to debug package)
• Pretty printing in development
• File logging support
• Next.js compatibility mode
• Configurable log levels
• Object and formatted string logging

Installation

npm install @very-coffee/hello

Basic Usage

import { helloInnit } from "@very-coffee/hello";

const namespaces = ["app", "api"] as const;
const levels = ["info", "error", "debug"] as const;

const hello = helloInnit(namespaces, levels);

// Log messages
hello.app.info("Server started on port %d", 3000);
hello.api.error({ error: new Error("Failed") }, "Request failed");

Configuration

Basic Options

const hello = helloInnit(namespaces, levels, {
  prettyPrint: true, // Enable pretty printing (default: true in development)
  level: "debug", // Set minimum log level
});

File Logging

const hello = helloInnit(namespaces, levels, {
  file: {
    path: "./logs/app.log", // Path to log file
    level: "info", // Optional: minimum level for file logging
    prettyPrint: true, // Optional: enable pretty printing in file
  },
});

Next.js Compatibility

For Next.js applications, especially in edge runtime environments where worker threads aren't supported:

// In your logger configuration file (e.g., src/lib/logs.ts)
import { helloInnit } from "@very-coffee/hello";

const namespaces = ["app", "api"] as const;
const levels = ["info", "error", "debug"] as const;

export const hello = helloInnit(namespaces, levels, {
  disableWorkers: true, // Required for Next.js edge runtime
  prettyPrint: process.env.NODE_ENV === "development",
});

When using in Next.js:

1. Always set disableWorkers: true to avoid worker thread errors
2. The logger will automatically use synchronous logging in edge runtime
3. File logging will use direct file streams instead of worker threads
4. Pretty printing will work in development mode without workers

Combined Configuration

You can combine different options:

const hello = helloInnit(namespaces, levels, {
  disableWorkers: true,
  prettyPrint: true,
  file: {
    path: "./logs/app.log",
    level: "info",
    prettyPrint: true,
  },
});

Environment Variables

DEBUG

Control which namespaces and levels are enabled:

# Enable specific namespace and level
DEBUG=app:info

# Enable all levels for a namespace
DEBUG=app:*

# Enable specific level across all namespaces
DEBUG=*:error

# Enable everything
DEBUG=*

# Enable multiple patterns
DEBUG=app:info,api:error

# Disable specific namespaces
DEBUG=*,-api

LOG_LEVEL

Set the minimum log level:

LOG_LEVEL=debug  # Will show debug and above
LOG_LEVEL=info   # Will show info and above
LOG_LEVEL=error  # Will show only error

NODE_ENV

Controls default pretty printing:

• development: Pretty printing enabled by default
• production: Pretty printing disabled by default
• test: Transport disabled by default

Advanced Usage

Custom Pino Configuration

You can pass any Pino options directly:

import { helloInnit, pino } from "@very-coffee/hello";

const hello = helloInnit(namespaces, levels, {
  // Any valid pino options
  timestamp: pino.stdTimeFunctions.isoTime,
});

Object Logging

// Log with context object
hello.app.info({ userId: "123" }, "User logged in");

// Log object directly
hello.app.debug({
  event: "cache_miss",
  key: "user_123",
});

Format Specifiers

Supports printf-style format specifiers:

• %s - String
• %d or %i - Integer
• %f - Float
• %o or %O - Object
• %j - JSON

Example:

hello.app.info("User %s logged in from %s", username, ip);

License

MIT