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Author message:

This package has been renamed to logita (https://www.npmjs.com/package/logita)

jl-log

🚧 Under construction, lots of breaking changes to be expected! 🚧

---

Overview

Simplistic logging for node.js with extensive TypeScript support.

Features:

• Customizable logging levels
• Display file path with line & column numbers (where the log function was called from)
• Can be used as flexibly as console.log or console.error with 1 or more arguments

Getting started

1. To use default logging settings, just import log.
2. To create logging object with custom settings, call createLoggers. Export the created logging object for your project needs.
3. Start logging!

Simplest example

// /app/src/some-file.ts
import { log } from "jl-log";

log.debug("Wow, this is cool!");

Example with some settings overridden

// /app/src/log.ts
import { createLoggers } from "jl-log";

export default createLoggers({
  showFile: false,
  // Use Moment.js format to format the timestamp!
  timestamp: "DD.MM.YYYY HH:mm:ss"
});

// /app/src/another-file.ts
import log from "./log";

log.debug("Wow, this is cool!");

Example with custom logging levels

import { createLoggers } from "jl-log";
// Use chalk to define log level colors!
import chalk from "chalk";

export default createLoggers({
  levels: {
    important: {
      priority: 0,
      color: chalk.bgRed.white,
      text: "UH-OH"
    },
    notSoImportant: {
      priority: 1,
      color: chalk.yellow,
      text: "meh"
    },
    silly: {
      priority: 2,
      color: chalk.green
    }
  },
  showFile: true,
  timestamp: "YYYY-MM-DD HH:mm:ss"
});

// /app/src/another-file.ts
import log from "./log";

log.important("Alarm!");
log.notSoImportant("Hello world");
log.silly("How do you do");

API

createLoggers(config)

Returns an object containing a simple logging function for each given logging level.

• config.levels (optional)
  • Default levels:
    • fatal (0)
    • error (1)
    • warning (2)
    • info (3)
    • verbose (4)
    • debug (5)
  • config.levels[level].priority (required)
    • Number
    • Defines the priority for logging level: the lower, more important the level is
  • config.levels[level].text (optional)
    • String
    • Log level text, shown in the prefix of the log message
    • Default: log level key in upper case
  • config.levels[level].color (optional)
    • Log level text color as a Chalk function
    • Default: chalk.bgBlack.bold.white
  • config.levels[level].stderr (optional)
    • Boolean
    • Should the log be directed to stderr instead of stdout?
    • Default: false
• config.minLevel (optional)
  • String (key of some log level)
  • Minimum log level that should be logged
  • Default: tries to find it from process.env.MIN_LOG_LEVEL, but if none is found, everything gets logged
• config.timestamp (optional)
  • Boolean or string
  • If false, timestamp is not shown
  • If true, timestamp is shown with Date.prototype.toUTCString
  • If string, timestamp is formatted with it using Moment.js
  • Default: true, i.e. show timestamp with Date.prototype.toUTCString
• config.showFile (optional)
  • Boolean
  • Should the file path be shown in the log message prefix?
  • Default: true

Default config:

{
  {
    levels: {
      fatal: {
        priority: 0,
        color: chalk.bgRedBright.white,
        stderr: true
      },
      error: {
        priority: 1,
        color: chalk.bgBlack.red,
        stderr: true
      },
      warning: {
        priority: 2,
        color: chalk.bgBlack.yellow
      },
      info: {
        priority: 3,
        color: chalk.bgBlack.blue
      },
      verbose: {
        priority: 4,
        color: chalk.bgBlack.green
      },
      debug: {
        priority: 5,
        color: chalk.bgKeyword("dimgray").white
      }
    }
  },
  showFile: true,
  timestamp: true,
  minLevel: process.env.LOG_MIN_LEVEL || undefined
}

Example log messages with default config: