atom/packages/line-ending-selector/lib/status-bar-item.js

const { Emitter } = require('atom')

module.exports = class StatusBarItem {
  constructor () {
    this.element = document.createElement('a')
    this.element.className = 'line-ending-tile inline-block'
    this.emitter = new Emitter()
    this.setLineEndings(new Set())
  }

  setLineEndings (lineEndings) {
    this.lineEndings = lineEndings
    this.element.textContent = lineEndingName(lineEndings)
    this.emitter.emit('did-change')
  }

  onDidChange (callback) {
    return this.emitter.on('did-change', callback)
  }

  hasLineEnding (lineEnding) {
    return this.lineEndings.has(lineEnding)
  }

  description () {
    return lineEndingDescription(this.lineEndings)
  }

  onClick (callback) {
    this.element.addEventListener('click', callback)
  }
}

function lineEndingName (lineEndings) {
  if (lineEndings.size > 1) {
    return 'Mixed'
  } else if (lineEndings.has('\n')) {
    return 'LF'
  } else if (lineEndings.has('\r\n')) {
    return 'CRLF'
  } else {
    return ''
  }
}

function lineEndingDescription (lineEndings) {
  switch (lineEndingName(lineEndings)) {
    case 'Mixed':
      return 'mixed'
    case 'LF':
      return 'LF (Unix)'
    case 'CRLF':
      return 'CRLF (Windows)'
    default:
      return 'unknown'
  }
}