yalo.js

Minimal Node.js logging library

const yalo = require("yalo.js")
const logger = yalo.createLogger("output.log")

logger.info("Hello, World!")
logger.error("Error occurred")

Installation

npm install yalo.js

No dependencies required

Usage

// configuration
const options = {
    depth: 2,
    errors: {
        title: "Error",
        format: ["=", "-"],
        width: 32,
        errorMode: true
    }
}

const logger = yalo.createLogger("output.log", options)

// log a data structure
const data = { user: { profile: { settings: { notifications: true } } } }
logger.info(data, "\n")

// show full structure
logger.depth = null
logger.info(data)

// error formatting examples
logger.error("Failed to load user data")
logger.error("Invalid configuration value", "Warning")
logger.error("Connection timeout", () => new Date().toLocaleTimeString())

logger.info("\nDone!")
logger.end()

Output:

{ user: { profile: { settings: [Object] } } }

{
  user: { profile: { settings: { notifications: true } } }
}

============ Error ============

Failed to load user data

-------------------------------

=========== Warning ===========

Invalid configuration value

-------------------------------

========== 10:08:36 AM ==========

Connection timeout

--------------------------------

Done!

Reference

createLogger(dest, options?)

createLogger(
	dest: string,
	options?: Partial<{
		depth: number | null
		errors: Partial<{
			title: string | (() => any)
			format: [string, string]
			width: number
			errorMode: boolean
		}>
	}>
)

• dest - Output file path
• options - Logger configuration
• options.depth - Object depth limit (default: 2)
• options.errors - Error decoration options
• options.errors.title - Error title (default: "Error")
• options.errors.format - Error decoration format (default: ["=", "-"])
• options.errors.width - Error decoration width (default: 80)
• options.errors.errorMode - Error-only streams optimization (default: false)

@returns

{
	fileStream: fs.WriteStream
	depth: number | null
	errors: {
		title: string | (() => any)
		format: [string, string]
		width: number
		errorMode: boolean
	}
	info(...data: any[]): void
	error(data: any, title?: string | (() => any)): void
	end(): void
}

• fileStream: Output stream
• depth: Object depth limit (options.depth)
• errors: Error decoration options (options.errors)
• info(): Logs info messages
• error(): Logs an error message
• end(): Ends output stream

info(data)

info(...data: any[]): void

• data - Any data

error(data, title?)

error(data: any, title?: string | (() => any)): void

• data - Any data
• title - Error title (errors.title)

end()

end(): void

• Ends output stream
• Used in loops

options.errors.errorMode

{
    errors: {
        errorMode: true
    }
}

• Error-only streams optimization (default: false)
• Removes the last \n from the output stream when calling error() to save space.
• Useful for server error-only log files

Examples

Error logger with Date()

const options = {
    errors: {
        title: () => new Date(),
        errorMode: true
    }
}

const logger = yalo.createLogger("error.log", options)

try {
    // ...
} catch (error) {
    logger.error(error)
}

License

MIT

Made for the Transmoder project