52 lines
1.7 KiB
JavaScript
52 lines
1.7 KiB
JavaScript
'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 anObject = require('../internals/an-object');
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var getIteratorDirect = require('../internals/get-iterator-direct');
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var notANaN = require('../internals/not-a-nan');
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var toPositiveInteger = require('../internals/to-positive-integer');
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var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
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var createIterResultObject = require('../internals/create-iter-result-object');
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var IS_PURE = require('../internals/is-pure');
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var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise) {
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var state = this;
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return new Promise(function (resolve, reject) {
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var doneAndReject = function (error) {
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state.done = true;
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reject(error);
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};
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var loop = function () {
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try {
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Promise.resolve(anObject(call(state.next, state.iterator))).then(function (step) {
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try {
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if (anObject(step).done) {
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state.done = true;
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resolve(createIterResultObject(undefined, true));
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} else if (state.remaining) {
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state.remaining--;
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loop();
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} else resolve(createIterResultObject(step.value, false));
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} catch (err) { doneAndReject(err); }
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}, doneAndReject);
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} catch (error) { doneAndReject(error); }
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};
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loop();
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});
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});
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// `AsyncIterator.prototype.drop` method
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// https://github.com/tc39/proposal-async-iterator-helpers
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$({ target: 'AsyncIterator', proto: true, real: true, forced: IS_PURE }, {
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drop: function drop(limit) {
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anObject(this);
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var remaining = toPositiveInteger(notANaN(+limit));
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return new AsyncIteratorProxy(getIteratorDirect(this), {
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remaining: remaining
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});
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}
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});
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