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esnext.async-iterator.flat-map.js
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esnext.async-iterator.flat-map.js
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'use strict';
// https://github.com/tc39/proposal-iterator-helpers
var $ = require('../internals/export');
var call = require('../internals/function-call');
var aCallable = require('../internals/a-callable');
var anObject = require('../internals/an-object');
var isObject = require('../internals/is-object');
var getIteratorDirect = require('../internals/get-iterator-direct');
var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
var createIterResultObject = require('../internals/create-iter-result-object');
var getAsyncIterator = require('../internals/get-async-iterator');
var closeAsyncIteration = require('../internals/async-iterator-close');
var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise) {
var state = this;
var iterator = state.iterator;
var mapper = state.mapper;
var innerIterator;
return new Promise(function (resolve, reject) {
var doneAndReject = function (error) {
state.done = true;
reject(error);
};
var ifAbruptCloseAsyncIterator = function (error) {
closeAsyncIteration(iterator, doneAndReject, error, doneAndReject);
};
var outerLoop = function () {
try {
Promise.resolve(anObject(call(state.next, iterator))).then(function (step) {
try {
if (anObject(step).done) {
state.done = true;
resolve(createIterResultObject(undefined, true));
} else {
var value = step.value;
try {
var result = mapper(value, state.counter++);
var handler = function (mapped) {
try {
state.innerIterator = innerIterator = getAsyncIterator(mapped);
state.innerNext = aCallable(innerIterator.next);
innerLoop();
} catch (error4) { ifAbruptCloseAsyncIterator(error4); }
};
if (isObject(result)) Promise.resolve(result).then(handler, ifAbruptCloseAsyncIterator);
else handler(result);
} catch (error3) { ifAbruptCloseAsyncIterator(error3); }
}
} catch (error2) { doneAndReject(error2); }
}, doneAndReject);
} catch (error) { doneAndReject(error); }
};
var innerLoop = function () {
if (innerIterator = state.innerIterator) {
try {
Promise.resolve(anObject(call(state.innerNext, innerIterator))).then(function (result) {
try {
if (anObject(result).done) {
state.innerIterator = state.innerNext = null;
outerLoop();
} else resolve(createIterResultObject(result.value, false));
} catch (error1) { ifAbruptCloseAsyncIterator(error1); }
}, ifAbruptCloseAsyncIterator);
} catch (error) { ifAbruptCloseAsyncIterator(error); }
} else outerLoop();
};
innerLoop();
});
});
$({ target: 'AsyncIterator', proto: true, real: true, forced: true }, {
flatMap: function flatMap(mapper) {
return new AsyncIteratorProxy(getIteratorDirect(this), {
mapper: aCallable(mapper),
innerIterator: null,
innerNext: null
});
}
});