import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
  name: 'first'
})
export class FirstPipe implements PipeTransform {

  transform(input: any): any {

    function convertToArray(object) {

      return Array.isArray(object) ? object : Object.keys(object).map(function (key) {

        return object[key];

      });

    }

    function getFirstElementMatch(array, index, query) {

      var count = 0;

      return array.filter(function (element) {

        var different = (typeof query !== undefined) ? (count < index && query(element)) : count < index;

        count = different ? count + 1 : count;

        return different;

      });

    }

    function isNumber(value) {

      return (typeof value === "number" && value !== null);

    }

    function isObject(object) {

      return (typeof object === "object" && object !== null) || typeof object === "function";

    }

    if (!String.prototype.includes) {

      String.prototype.includes = function () {

        return String.prototype.indexOf.apply(this, arguments) !== -1;

      };

    }

    let index,
      getter,
      args;

    input = isObject(input) ? convertToArray(input) : input;

    if (!Array.isArray(input)) {

      return input;

    }

    args = Array.prototype.slice.call(arguments, 1);
    index = (isNumber(args[0])) ? args[0] : 1;
    getter = (!isNumber(args[0])) ? args[0] : (!isNumber(args[1])) ? args[1] : undefined;

    return args.length ? getFirstElementMatch(input, index, (getter) ? String(getter) : getter) : input[0];
  }

}