import { Cls } from './types';

export function isFunction(obj: any): obj is Function {
  return typeof obj === 'function';
}

export function isClass<T = any>(cls: any): cls is Cls<T> {
  return isFunction(cls) &&
    cls.hasOwnProperty('prototype') &&
    cls.prototype.constructor === cls;
}

/**
 * Returns the string name of an object
 * See https://github.com/angular/angular/blob/2.0.0-rc.4/modules/%40angular/facade/src/lang.ts#L149
 */
export function stringify(token: any): string {
  if (typeof token === 'string') {
    return token;
  }

  if (token === undefined || token === null) {
    return '' + token;
  }

  if (token.name) {
    return token.name;
  }
  if (token.overriddenName) {
    return token.overriddenName;
  }

  const res = token.toString();
  const newLineIndex = res.indexOf('\n');
  return newLineIndex === -1 ? res : res.substring(0, newLineIndex);
}