@ocelotjungle/logger

This package provides a Logger class with configurable outputs and levels, and ability to create subloggers.

Usage

Constructor

It takes either nothing or just logger name or an options object:

• name is a name of a logger;
• options:
  • dateFormatter is a function that stringifies Date, can be one of presets or custom;
  • levels can be:
    • max level that is written to logs (for example, error, then warnings, info etc won't be printed);
    • object with explicitly defined levels;
  • unite - if true, then all outputs are accumulated till you use end();
  • defaultLogOptions is a log options that are applied to every log by default;

Methods

withConsole

Adds console to logger outputs. Can be default (global.console) or custom.

withFiles

Adds files to logger outputs:

• folder is an absolute path or relative to project root path where logs will be written;
• name is a left log files name (*name*(.suffix)?.extension);
• extension is a log files extension (name(.suffix)?.*extension*);
• levels is similar to constructor's options levels, except common level, which is general file for all logs;

Logging functions

• error - level 1, errors;
• warn - level 2, warnings;
• info - level 3, info messages;
• dev - level 4, info messages for development/debugging;
• end - frees accumulated messages if unite, else does nothing;

Utils

• sub - creates sublogger, copying the master logger parameters;
• bound - returns a scope of logger functions, bound to the logger;

Examples

const logger = new Logger("master logger").withConsole()
logger.info("sample info message") // [iso-datetime] (master logger) ||| sample info message

const sublogger = logger.sub("sublogger", unite = true)
const { dev, env } = sublogger
dev("dev message 1") // prints nothing
dev("dev message 2") // prints nothing
end() // prints both previous messages in one operation, not broken my any other logger intermediate output

const subsublogger = sublogger.sub("subsublogger", unite = false, { depth: null })
subsublogger.error({ foo: { bar: { ... } } }) // prints argument inspected with no depth constraint, as console.dir(..., { depth: null }) would