'use strict';
var $ = require('../internals/export');
var call = require('../internals/function-call');
var anObject = require('../internals/an-object');
var getIteratorDirect = require('../internals/get-iterator-direct');
var notANaN = require('../internals/not-a-nan');
var toPositiveInteger = require('../internals/to-positive-integer');
var createIteratorProxy = require('../internals/iterator-create-proxy');

var IteratorProxy = createIteratorProxy(function () {
  var iterator = this.iterator;
  var next = this.next;
  var result, done;
  while (this.remaining) {
    this.remaining--;
    result = anObject(call(next, iterator));
    done = this.done = !!result.done;
    if (done) return;
  }
  result = anObject(call(next, iterator));
  done = this.done = !!result.done;
  if (!done) return result.value;
});

// `Iterator.prototype.drop` method
// https://github.com/tc39/proposal-iterator-helpers
$({ target: 'Iterator', proto: true, real: true }, {
  drop: function drop(limit) {
    return new IteratorProxy(getIteratorDirect(this), {
      remaining: toPositiveInteger(notANaN(+limit))
    });
  }
});