mirror of
https://github.com/musix-org/musix-oss
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68 lines
2.4 KiB
JavaScript
68 lines
2.4 KiB
JavaScript
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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 aFunction = require('../internals/a-function');
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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 getAsyncIteratorMethod = require('../internals/get-async-iterator-method');
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var AsyncIteratorProxy = createAsyncIteratorProxy(function (arg, Promise) {
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var state = this;
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var mapper = state.mapper;
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var innerIterator, iteratorMethod;
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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(state.next.call(state.iterator, arg))).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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iteratorMethod = getAsyncIteratorMethod(mapped);
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if (iteratorMethod !== undefined) {
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state.innerIterator = innerIterator = anObject(iteratorMethod.call(mapped));
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state.innerNext = aFunction(innerIterator.next);
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return innerLoop();
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} reject(TypeError('.flatMap callback should return an iterable object'));
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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(state.innerNext.call(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 }, {
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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: aFunction(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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