Kantan Logger

A simple but hopefully versatile logger.
Kantan Logger creates a log directory. In that directory Kantan Logger creates a directory with the date (MM.DD.YY). Log files are then titled with a time stamp (HH.MM.SS.MMM) from when they were created.

Installing

Install via pnpm

pnpm i kantan-logger

Getting Started

// node/common.js style 
const kantan = require('kantan-logger')

Usage

kantan.log(obj1 [, obj2, ..., objN])

obj1 ... objN - A list of JavaScript objects to write to the log file. The string representations of these objects are appended together in the order listed and written.

To start a new instance of the logger or a new file to write:

kantan.create(obj1)

obj1 - Object with the optional properties; title, location and directory.

Options

Option | Default | Notes --- | --- | --- title | '' | Prepends the title to the log file name location | '' | Relative to the directory from which your main file is run directory | 'logs' | Name of the logs directory logLevels | ['success', 'verbose', 'info', 'warning', 'error'] | Names of the log levels you require logLevelWebhooks | {} | Object where the property is the log level to trigger a webhook, and the value is the URL to post to useTimeInTitle | true | Include a time stamp in the log file name useDateDirectories | true | Separate log files into date‑based subdirectories daysTillDelete | 7 | Number of days of logs to keep before deletion prettyJSON | true | Prettify JSON output in log entries prettyText | true | Formats text output without extra string literal quotes echoToConsole | false | Echoes logs to the console useJSON | false | When true, writes each log entry as a full JSON object in a newline‑delimited JSON file (extension: .jsonl) showMemoryUsage | false | Includes memory usage statistics in the log entry

JSON Output

When the useJSON option is set to true, each log entry is output using JSON.stringify (with formatting if enabled by prettyJSON). The log file is created with a .jsonl extension and consists of individual, newline‑separated JSON objects. This format is suitable for processing with tools that support JSON lines.

Use Case

For example: You have an application that continuously listens for POST requests. For each post, a new log instance is created:

// server related requires and setup
const express = require('express')
const kantan = require('kantan-logger')

const port = process.env.PORT || 3001
const app = express()

app.use(express.urlencoded({ extended: false }))
app.use(express.json())

// Start listening on port
app.listen(port, () => {
  console.log(`port up on ${port}`)
})

// Listen for POST requests
app.post('/', (req, res) => {
  res.writeHead(200, { 'Content-Type': 'text/html' })
  res.end('Thanks')

  // Create a new instance of kantan for this post.
  // The title is prefixed with the req.body.ticketId.
  const logger = kantan.create({
    title: req.body.ticketId,
    logLevels: ['ichi', 'ni', 'san', 'shi', 'go'],
    logLevelWebhooks: {
      ichi: 'http://localhost:3000/ichi-data-goes-here'
    }
  })

  // Calling with a log level.
  logger.ichi({
    info: 'when pushing a webhook the first argument must be an object',
    moreInfo: 'it can contain any additional parameters you would like to post',
    andMoreInfo: 'the current log level and message will also be posted as *level* & *message*'
  }, 'log messages here', 'and another', ['arrays', 'and', 'objects', 'are', 'also', 'ok'])

  // Additional log output.
  logger.log('information logged here')
})

Authors

• Matt Shostak - Initial work - Github
• Will Shostak - Initial work - Github

See also the list of contributors who participated in this project.

License

This project is licensed under the ISC License.