index.js

var _ = {toArray: require('lodash.toarray')}

class EmojiConverter{

  /**
  * Create an emoji converter instance
  * 
  * @constructor
  * @param sources an array of emoji sources. Default is `[EmojiConverter.EMOJI_DEFAULT_SOURCE]`
  */
  constructor(sources){

    this.sources = sources
    if (!this.sources){
      this.sources = [EmojiConverter.EMOJI_DEFAULT_SOURCE]
    }

    // emojiMap is shortcode:unicode
    this.emojiMap = {}
    // shortcodeMap is unicode:shortcode
    this.shortcodeMap = {}
    // aliasMap is alias:shortcode
    this.aliasMap = {}
    // nameMap is shortcode:name
    this.nameMap = {}
    // objectMap shortcode:object
    this.objectMap = {}

    this.sources.forEach(source =>{

      // array format (may be missing unicode character. see README.)
      if (Array.isArray(source)){

        source.forEach(item=>{
          var unicode = item.unicode
          var shortname = item.shortname
          var name = item.name || shortname.replace(/\:/g,'')
          var shortnames = [shortname, ...(item.shortname_alternates || []) ]
          
          shortnames.forEach(s=>{
            if (unicode){
              this.emojiMap[s] = unicode
            }
            this.aliasMap[s] = shortname
          })

          if (unicode) { this.shortcodeMap[unicode] = shortname }
          this.nameMap[shortname] = item.name || shortname.replace(/\:/g,'')
          this.objectMap[shortname] = item
        })

        return
      }

      // object format (from emoji-toolkit/emoji_strategy.json)
      // iterate through each key (key is the unicode sequence)
      Object.keys(source).forEach(sequence=>{

        var entry = source[sequence]
        var unicode = EmojiConverter.pointsStringToUnicode(entry['unicode_output'])
           
        var shortname = entry.shortname;
        var shortnames = [shortname, ...entry.shortname_alternates]

        shortnames.forEach(s=>{
          this.emojiMap[s.toLowerCase()] = unicode
          this.aliasMap[s.toLowerCase()] = shortname
        })

        this.shortcodeMap[unicode] = shortname
        this.nameMap[shortname] = entry.name || shortname.replace(/\:/g,'')
        this.objectMap[shortname] = entry

      })
    })

  }

  // replacer function takes in (unicode, shortcode, name)

  /**
   * Replace unicode in a string with a custom function
   * @param {string} str the string to operate on
   * @param {function} replacer the replacer function
   * @returns {string} the resultant string
   */
  replaceUnicodeWith(str, replacer){
    return _.toArray(str)
      .map(s => {
        var shortcode = this.shortcodeMap[s];
        if (shortcode){
          var name = this.nameMap[shortcode]||'';
          var obj = this.objectMap[shortcode]||{}
          return replacer(s, shortcode, name, obj)
        } else { // no short code for this unicode char. i.e. we don't have this.
          return s
        }
      })
      .join('')
  }

  /**
   * Replace shortcodes in a string with a custom function
   * @param {string} str the string to operate on
   * @param {function} replacer the replacer function
   * @returns {string} the resultant string
   */
  replaceShortcodesWith(str, replacer){
    return str.replace(EmojiConverter.SHORTCODE_REGEX, (match)=>{
      var short = match.toLowerCase()
      var uni = this.emojiMap[short]||''
      var name = this.nameMap[short]||''
      var obj = this.objectMap[short]||{}
      return replacer(uni, short, name, obj)
    })
  }

  /**
   * Replace unicode and shortcodes in a string with a custom function
   * @param {string} str the string to operate on
   * @param {function} replacer the replacer function
   * @returns {string} the resultant string
   */
  replaceWith(str, replacer){
    return this.replaceShortcodesWith(this.replaceUnicode(str), replacer)
  }

  /**
   * Replace unicode in a string with shortcodes
   * @param {string} str the string to operate on
   * @param {function} replacer the replacer function
   * @returns {string} the resultant string
   */
  replaceUnicode(str){
    return _.toArray(str)
      .map(s => this.shortcodeMap[s] || s)
      .join('')
  }

  /**
   * Replace shortcodes in a string with unicode
   * @param {string} str the string to operate on
   * @param {function} replacer the replacer function
   * @returns {string} the resultant string
   */
  replaceShortcodes(str){
    return str.replace(EmojiConverter.SHORTCODE_REGEX, (match)=>{
      return this.emojiMap[match.toLowerCase()] || match
    })
  }

  /**
   * Replace short codes with their more normalized version.
   * @param {string} str the string to operate on
   * @returns {string} the resultant string
   */
  normalizeShortcodes(str){
    return str.replace(EmojiConverter.SHORTCODE_REGEX, (match)=>{
      return this.aliasMap[match.toLowerCase()] || match
    })
  }

}

/**
 * Convert a single unicode emoji to a string representing codepoints (such as '1f646-1f3ff-2642')
 * @param {string} str the unicode sequence you want converted
 * @returns {string}
 */
EmojiConverter.unicodeToPointsString = function(str){
  return Array.from(str).map(s => s.codePointAt(0).toString(16) ).join('-')
}

/**
 * Convert a string representing unicode codepoints (such as '1f646-1f3ff-2642')
 * @param {string} str the unicode sequence you want converted
 * @returns {string}
 */
EmojiConverter.pointsStringToUnicode = function(str){
  var unicode = ''
  var codes = str.split('-')
  for (var i = 0; i < codes.length; i ++){
    unicode += String.fromCodePoint(Number('0x'+codes[i]))
  }
  return unicode
}

EmojiConverter.EMOJI_DEFAULT_SOURCE = require('emoji-toolkit/emoji_strategy.json')

EmojiConverter.SHORTCODE_REGEX = /(\:(\w|\+|\-)+\:)/gim

module.exports = EmojiConverter;