index.ts

import util from 'util'
import debugModule from 'debug'
import linewise from 'linewise'
import { Writable, Duplex } from 'stream'

const debug = debugModule('slate-irc-parser')

export default class Parser extends Writable {
  nlstream: Duplex

  /**
   * Initialize IRC parser.
   *
   * @api public
   */
  constructor() {
    super()
    this.nlstream = linewise.getPerLineBuffer()
    this.nlstream.on('data', this.online.bind(this))
    this.nlstream.resume()
  }

  /**
   * Write `chunk`.
   *
   * @param {Buffer} chunk
   * @api public
   */
  write(chunk: Buffer): boolean {
    return this.nlstream.write(chunk)
  }

  /**
   * Parse lines and emit "message" events.
   *
   * @param {String} line
   * @api private
   */
  online(line: String): void {
    // Remove a single CR at the end of the line if it does exist
    line = line.replace(/\r$/, '')

    debug('line %s', util.inspect(line))
    const orig = line

    // prefix
    let prefix
    if (':' == line[0]) {
      const i = line.indexOf(' ')
      prefix = line.slice(1, i)
      line = line.slice(i + 1)
    }

    // command
    let i = line.indexOf(' ')
    if (-1 == i) i = line.length
    const command = line.slice(0, i)
    line = line.slice(i)

    // params
    i = line.indexOf(' :')
    if (-1 == i) i = line.length
    const params = line.slice(1, i)
    line = line.slice(i + 2)

    const msg = {
      prefix: prefix || '',
      command: command,
      params: params || '',
      trailing: line || '',
      string: orig,
    }

    debug('message %j', msg)
    this.emit('message', msg)
  }

  /**
   * Emit "end".
   *
   * @api public
   */
  end() {
    this.emit('end')
    return this
  }
}