const _toString = Object.prototype.toString
const simpleCheckRE = /^(String|Number|Boolean|Function|Symbol)$/

function getType (fn) {
  const match = fn && fn.toString().match(/^\s*function (\w+)/)
  return match ? match[1] : ''
}
function isPlainObject (obj) {
  return _toString.call(obj) === '[object Object]'
}

function assertType (value, type) {
  let valid
  const expectedType = getType(type)
  if (simpleCheckRE.test(expectedType)) {
    const t = typeof value
    valid = t === expectedType.toLowerCase()
    // for primitive wrapper objects
    if (!valid && t === 'object') {
      valid = value instanceof type
    }
  } else if (expectedType === 'Object') {
    valid = isPlainObject(value)
  } else if (expectedType === 'Array') {
    valid = Array.isArray(value)
  } else {
    valid = value instanceof type
  }
  return valid;
}

module.exports = assertType;