119 lines
3.4 KiB
Plaintext
119 lines
3.4 KiB
Plaintext
'use strict';
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var $TypeError = require('es-errors/type');
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var Call = require('es-abstract/2023/Call');
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var CompletionRecord = require('es-abstract/2023/CompletionRecord');
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var CreateIteratorFromClosure = require('../aos/CreateIteratorFromClosure');
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var GetIteratorDirect = require('../aos/GetIteratorDirect');
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var GetIteratorFlattenable = require('../aos/GetIteratorFlattenable');
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var IsCallable = require('es-abstract/2023/IsCallable');
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var IteratorClose = require('../aos/IteratorClose');
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var IteratorStepValue = require('../aos/IteratorStepValue');
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var ThrowCompletion = require('es-abstract/2023/ThrowCompletion');
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var Type = require('es-abstract/2023/Type');
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var iterHelperProto = require('../IteratorHelperPrototype');
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var SLOT = require('internal-slot');
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module.exports = function flatMap(mapper) {
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if (this instanceof flatMap) {
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throw new $TypeError('`flatMap` is not a constructor');
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}
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var O = this; // step 1
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if (Type(O) !== 'Object') {
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throw new $TypeError('`this` value must be an Object'); // step 2
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}
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if (!IsCallable(mapper)) {
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throw new $TypeError('`mapper` must be a function'); // step 3
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}
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var iterated = GetIteratorDirect(O); // step 4
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var sentinel = { sentinel: true };
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var innerIterator = sentinel;
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var closeIfAbrupt = function (abruptCompletion) {
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if (!(abruptCompletion instanceof CompletionRecord)) {
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throw new $TypeError('`abruptCompletion` must be a Completion Record');
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}
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try {
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if (innerIterator !== sentinel) {
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IteratorClose(
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innerIterator,
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abruptCompletion
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);
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}
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} finally {
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innerIterator = sentinel;
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IteratorClose(
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iterated,
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abruptCompletion
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);
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}
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};
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var counter = 0; // step 5.a
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var innerAlive = false;
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var closure = function () {
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// while (true) { // step 5.b
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if (innerIterator === sentinel) {
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var value = IteratorStepValue(iterated); // step 5.b.i
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if (iterated['[[Done]]']) {
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innerAlive = false;
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innerIterator = sentinel;
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// return void undefined; // step 5.b.ii
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return sentinel;
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}
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}
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if (innerIterator === sentinel) {
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innerAlive = true; // step 5.b.viii
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try {
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var mapped = Call(mapper, void undefined, [value, counter]); // step 5.b.iv
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// yield mapped // step 5.b.vi
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innerIterator = GetIteratorFlattenable(mapped, 'reject-strings'); // step 5.b.vi
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} catch (e) {
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innerAlive = false;
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innerIterator = sentinel;
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closeIfAbrupt(ThrowCompletion(e)); // steps 5.b.v, 5.b.vii
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} finally {
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counter += 1; // step 5.b.x
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}
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}
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// while (innerAlive) { // step 5.b.ix
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if (innerAlive) {
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// step 5.b.ix.4
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var innerValue;
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try {
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innerValue = IteratorStepValue(innerIterator); // step 5.b.ix.4.a
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} catch (e) {
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innerAlive = false;
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innerIterator = sentinel;
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closeIfAbrupt(ThrowCompletion(e)); // step 5.b.ix.4.b
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}
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if (innerIterator['[[Done]]']) {
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innerAlive = false;
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innerIterator = sentinel;
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return closure();
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}
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return innerValue; // step 5.b.ix.4.c
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}
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// }
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// return void undefined;
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return sentinel;
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};
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SLOT.set(closure, '[[Sentinel]]', sentinel); // for the userland implementation
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SLOT.set(closure, '[[CloseIfAbrupt]]', closeIfAbrupt); // for the userland implementation
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var result = CreateIteratorFromClosure(closure, 'Iterator Helper', iterHelperProto, ['[[UnderlyingIterator]]']); // step 7
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SLOT.set(result, '[[UnderlyingIterator]]', iterated); // step 8
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return result; // step 9
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};
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