cu-mongoose-troop/lib/keywords/index.js

a collection of plugins for mongoose

/*!
 * Copyright(c) Beau Sorensen, Thomas Blobaum
 * MIT Licensed
 */

function keywords (schema, options) {
  options || (options = {})

  var target = options.target || 'keywords'    // Field to put the keywords array
    , source = options.source                  // Field to extract keywords from
    , minLength = options.minLength || 2       // Minimum keyword length
    , invalidChar = options.invalidChar || ''  // Invalid char replacement
    , naturalize = options.naturalize || false // Natural language stemming
    , fr = 'àáâãäåçèéêëìíîïñðóòôõöøùúûüýÿ'     // Accent chars to find
    , to = 'aaaaaaceeeeiiiinooooooouuuuyy'     // Accent replacement
    , fields = {}
    , PorterStemmer = require('./porter_stemmer')

  if (!(source instanceof Array)) source = [ source ]
  
  if (!schema.paths[target]) {
    fields[target] = [ String ]
  }

  for (var i = 0; i < source.length; i++) {
    if (!schema.paths[source[i]]) {
      fields[source[i]] = String
    }
  }

  schema.add(fields)
  
  schema.pre('save', function (next) {
    var words = []
    for (var i = 0; i < source.length; i++) {
      var add = this.extractKeywords(this[source[i]])
      for (var s = 0; s < add.length; s++) {
        if (!~words.indexOf(add[s])) words.push( add[s] )
      }
    }
    this[target] = words
    next()
  })
  
  ;['static'
  , 'method'
  ].forEach(function (method) {
    schema[method]('extractKeywords', function (str) {
      if (!str) return []
      str = str
        .replace(/^\s+|\s+$/g, '')
        .toLowerCase()
      
      for (var i=0; i<fr.length; i++) {
        str = str.replace(new RegExp(fr.charAt(i), 'g'), to.charAt(i))
      }
      str = str
        .replace(/[^a-z0-9 -]/g, invalidChar)
        .replace(new RegExp('['+invalidChar+']'+'+', 'g'), invalidChar)
        .split(/\s+/)
        .filter(function (v) { return v.length >= minLength })
        .filter(function (v, i, a) { return a.lastIndexOf(v) === i })
      
      if (naturalize) {
        str.forEach(function (v, i, arr) {
          arr[i] = PorterStemmer.stem(v)
        })
      }
      return str
    })
  })
}

module.exports = keywords