code: function compressible (type) {
    if (!type || typeof type !== 'string') {
      return false
    }
  
    // strip parameters
    var match = EXTRACT_TYPE_REGEXP.exec(type)
    var mime = match && match[1].toLowerCase()
    var data = db[mime]
  
    // return database information
    if (data && data.compressible !== undefined) {
      return data.compressible
    }
  
    // fallback to regexp or unknown
    return COMPRESSIBLE_TYPE_REGEXP.test(mime) || undefined
  }
docs: Checks if a type is compressible.
  
  @param {string} type
  @return {Boolean} compressible
  @public