import typechecker from 'typechecker'

const customTypeChecker = Object.assign({}, typechecker)  // typechecker is frozen

// add custom types
customTypeChecker.isPromise = function isPromise(obj) {
  return !!obj && (typeof obj === 'object' || typeof obj === 'function') && typeof obj.then === 'function'
}

customTypeChecker.isBuffer = function isBuffer(obj) {
  return !!obj.constructor && typeof obj.constructor.isBuffer === 'function' && obj.constructor.isBuffer(obj)
}

// Add custom types to typeMap
let customTypeMap = {
  buffer: customTypeChecker.isBuffer,
  promise: customTypeChecker.isPromise
}

customTypeMap = Object.assign(customTypeMap, customTypeChecker.typeMap)

customTypeChecker.getType = function customGetType(value, _typeMap) {
  return typechecker.getType(value, _typeMap || customTypeMap)
}

export default customTypeChecker
export { customTypeChecker as type }