nn-node-log

Simple Node log

Simple Node log with levels, color, and log location from file name and line number, inspired from the Golang log package.

• Caution: This package uses some private APIs from Node, those APIs are not guaranteed to be kept overtime. It's also a new package under heavy developing and has not been well tested yet. If any problem happens, feel free to open an issue.
• Require:
  • Node >= v8.0.0

Reference

• Example
• API

Example

const log = require('nn-node-log')

try {
  process.on('uncaughtException', (err) => {
    log.stack(err)
  })

  // init our express app, router, graphql...

  server.listen(8080, () => log.info('listening on port 8080'))
} catch (err) {
  log.stack(err, 'fatal')
}

API

The exported module is a singleton of lib/Log class. It has the following properties and methods:

log.level

• string - Default debug
• A string to specify the current log level of the instance. It should be one of debug, info, warn, error or fatal.

log.debugPrefix

• string - Default is an empty string
• A string to specify the debug prefix to filter out the unnecessary debug messages.

log.color

• A boolean flag to indicate that it should print with color or not. Default is true.

log.skip

• number - Default 3
• A number to skip when retrieving the stack trace call layer. We should modify this number when we want to wrap the library inside other function calls.

log.timezone

• number - Default is the current timezone
• A number to specify the target timezone to be printed out.

log.setCwd(cwd)

• Set the current working directory
• Parameters:
  • cwd:
    • string - Required

log.filterFn

• Function - Default from the stacktrace package
• A function to filter the stack layer.

log.filenameFn

• Function - Default from the stacktrace package
• A function to get the shortened file name from the stack layer.

log.debug([f, ...args])

log.warn([f, ...args])

log.info([f, ...args])

log.error([f, ...args])

log.fatal([f, ...args])

• Log with a specified format for each level. With fatal level, it will call process.exit(1) to quit the current process afterwards.
• Parameters:
  • f:
    • string|any - Optional
    • The format pattern. See Node util.format API for detail.
  • ...args:
    • any - Optional
    • The rest arguments to be formatted with.

log.trace(level[, f, ...args])

• Print out together with the call layers.
• Parameters:
  • level:
    • string - Required
    • A string to specify the level to log.
  • f:
    • string|any - Optional
    • The format pattern. See Node util.format API for detail.
  • ...args:
    • any - Optional
    • The rest arguments to be formatted with.

log.stack(err[, level])

• Pretty print out the error.
• Parameters:
  • err:
    • Error - Required
    • The error to be printed out.
  • level:
    • string - Optional - Default error
    • A string to specify the level to log.

License

MIT