function splitType(string) {
  var match = typeRegExp.exec(string.toLowerCase())

  if (!match) {
    throw new TypeError('invalid media type')
  }

  var type = match[1]
  var subtype = match[2]
  var suffix

  // suffix after last +
  var index = subtype.lastIndexOf('+')
  if (index !== -1) {
    suffix = subtype.substr(index + 1)
    subtype = subtype.substr(0, index)
  }

  var obj = {
    type: type,
    subtype: subtype,
    suffix: suffix
  }

  return obj
}
Simply "type/subtype+siffx" into parts.

@param {string} string
@return {Object}
@api private