'use strict';
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var $ = require('../internals/export');
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var call = require('../internals/function-call');
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var aCallable = require('../internals/a-callable');
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var anObject = require('../internals/an-object');
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var getIteratorDirect = require('../internals/get-iterator-direct');
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var getIteratorFlattenable = require('../internals/get-iterator-flattenable');
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var createIteratorProxy = require('../internals/iterator-create-proxy');
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var iteratorClose = require('../internals/iterator-close');
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var IS_PURE = require('../internals/is-pure');
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var IteratorProxy = createIteratorProxy(function () {
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var iterator = this.iterator;
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var mapper = this.mapper;
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var result, inner;
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while (true) {
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if (inner = this.inner) try {
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result = anObject(call(inner.next, inner.iterator));
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if (!result.done) return result.value;
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this.inner = null;
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} catch (error) { iteratorClose(iterator, 'throw', error); }
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result = anObject(call(this.next, iterator));
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if (this.done = !!result.done) return;
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try {
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this.inner = getIteratorFlattenable(mapper(result.value, this.counter++), false);
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} catch (error) { iteratorClose(iterator, 'throw', error); }
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}
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});
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// `Iterator.prototype.flatMap` method
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// https://github.com/tc39/proposal-iterator-helpers
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$({ target: 'Iterator', proto: true, real: true, forced: IS_PURE }, {
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flatMap: function flatMap(mapper) {
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anObject(this);
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aCallable(mapper);
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return new IteratorProxy(getIteratorDirect(this), {
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mapper: mapper,
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inner: null
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});
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}
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});
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