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66 lines
2.2 KiB
66 lines
2.2 KiB
2 years ago
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'use strict';
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// https://github.com/tc39/proposal-iterator-helpers
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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 createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
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var getAsyncIterator = require('../internals/get-async-iterator');
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var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise) {
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var state = this;
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var mapper = state.mapper;
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var innerIterator;
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return new Promise(function (resolve, reject) {
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var outerLoop = 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({ done: true, value: undefined });
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} else {
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Promise.resolve(mapper(step.value)).then(function (mapped) {
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try {
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state.innerIterator = innerIterator = getAsyncIterator(mapped);
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state.innerNext = aCallable(innerIterator.next);
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return innerLoop();
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} catch (error2) { reject(error2); }
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}, reject);
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}
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} catch (error1) { reject(error1); }
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}, reject);
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} catch (error) { reject(error); }
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};
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var innerLoop = function () {
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if (innerIterator = state.innerIterator) {
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try {
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Promise.resolve(anObject(call(state.innerNext, innerIterator))).then(function (result) {
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try {
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if (anObject(result).done) {
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state.innerIterator = state.innerNext = null;
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outerLoop();
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} else resolve({ done: false, value: result.value });
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} catch (error1) { reject(error1); }
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}, reject);
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} catch (error) { reject(error); }
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} else outerLoop();
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};
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innerLoop();
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});
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});
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$({ target: 'AsyncIterator', proto: true, real: true, forced: true }, {
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flatMap: function flatMap(mapper) {
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return new AsyncIteratorProxy({
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iterator: anObject(this),
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mapper: aCallable(mapper),
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innerIterator: null,
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innerNext: null
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});
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}
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});
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