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Add an Iterator.from TypeScript goody (#417)
based off of [MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Iterator/from) closes #343
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‎workspaces/adventure-pack/goodies/typescript/Iterator.from/index.test.ts‎

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import { describe, expect, it } from "@jest/globals";
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import "../Iterator.prototype.map";
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import "../Iterator.prototype.filter";
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(globalThis as Record<string, unknown>).Iterator &&
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delete (
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(globalThis as Record<string, unknown>).Iterator as Record<string, unknown>
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).from;
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// eslint-disable-next-line import-x/first
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import "./index";
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describe("Iterator.from", () => {
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it("can convert an Array to an Iterator", () => {
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const array = [-3, 1, -4, 1, -5];
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const iterator = Iterator.from(array);
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expect([...iterator]).toStrictEqual(array);
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});
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it("can convert a Set to an Iterator", () => {
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const set = new Set([-3, 1, 1, -4, -4, 1, -5]);
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const iterator = Iterator.from(set);
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expect([...iterator]).toStrictEqual([...set]);
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});
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it("can convert a Map to an Iterator", () => {
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const map = new Map([
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["z", 3],
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["e", 1],
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["d", 4],
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]);
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const iterator = Iterator.from(map);
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expect([...iterator]).toStrictEqual([...map.entries()]);
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});
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it("can convert a Generator Object to an Iterator", () => {
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const factory = function* (): Generator<number, void, void> {
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yield 3;
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yield 1;
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yield 4;
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yield 1;
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yield 5;
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};
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const iterator = Iterator.from(factory());
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expect([...iterator]).toStrictEqual([3, 1, 4, 1, 5]);
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});
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it("can convert a String to an Iterator", () => {
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const string = "🚀💯🔥";
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const iterator = Iterator.from(string);
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expect([...iterator]).toStrictEqual([...string]);
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});
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it("can convert an Iterator to an IterableIterator and returns the same reference", () => {
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const array = [-3, 1, -4, 1, -5];
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const iterator = array.values();
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const convertedIterator = Iterator.from(iterator);
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expect(convertedIterator).toBe(iterator);
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});
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it("can convert an IterableIterator to an Iterator", () => {
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const array = [-3, 1, -4, 1, -5];
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const iterator = Iterator.from(array.values());
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const iterator2 = Iterator.from(iterator[Symbol.iterator]());
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expect([...iterator2]).toStrictEqual(array);
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});
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it("can convert an object with a random next() method to an Iterator", () => {
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const object = {
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values: [-3, 1, -4, 1, -5, 9],
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index: 0,
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next(): IteratorResult<number, void> {
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if (this.index < this.values.length) {
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return { value: this.values[this.index++], done: false };
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}
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return { done: true, value: undefined };
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},
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};
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const iterator = Iterator.from(object)
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.map((x) => x * 2)
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.filter((x) => x > 0);
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expect([...iterator]).toStrictEqual([2, 2, 18]);
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});
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it("throws an error if the object is not an Iterator, Iterable, or an object with a next method", () => {
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const object = {};
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// @ts-expect-error Invalid argument
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expect(() => Iterator.from(object)).toThrow(TypeError);
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});
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});

‎workspaces/adventure-pack/goodies/typescript/Iterator.from/index.ts‎

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import "../Iterator.prototype.toIterable/index.ts";
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import { iteratorPrototype } from "../Iterator.prototype/index.ts";
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declare global {
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interface IteratorConstructor {
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from<T>(
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object: Iterator<T> | Iterable<T> | { next(): IteratorResult<T> },
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): IterableIterator<T>;
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}
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const Iterator: IteratorConstructor;
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}
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(globalThis as Record<string, unknown>).Iterator ??= {};
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((globalThis as Record<string, unknown>).Iterator as { from: unknown }).from ??=
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function <T>(
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object: Iterator<T> | Iterable<T> | { next(): IteratorResult<T> },
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): IterableIterator<T> {
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const toIterable = iteratorPrototype.toIterable as (
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this: Iterator<T>,
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) => IterableIterator<T>;
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const iteratorFactory = (object as Iterable<T>)[Symbol.iterator];
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if (typeof iteratorFactory === "function") {
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return toIterable.call(iteratorFactory.call(object));
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}
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// eslint-disable-next-line no-prototype-builtins
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if (iteratorPrototype.isPrototypeOf(object)) {
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return toIterable.call(object as Iterator<T>);
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}
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if (typeof (object as Record<string, unknown>).next === "function") {
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return (function* () {
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yield* toIterable.call(object as Iterator<T>);
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})();
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}
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throw new TypeError(
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"Object is not an iterator, iterable, or an object with a next method",
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);
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};

‎workspaces/adventure-pack/src/app/__tests__/__snapshots__/equip-test.ts.snap‎

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@@ -1364,6 +1364,53 @@ Function.returnThis = function () {
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/////////////////////////// END ADVENTURE PACK CODE ////////////////////////////"
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`;
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exports[`App can equip single goody: JavaScript Iterator.from 1`] = `
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"////////////////////////// BEGIN ADVENTURE PACK CODE ///////////////////////////
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// Adventure Pack commit fake-commit-hash
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// Running at: https://example.com/
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Function.returnThis = function () {
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return this;
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};
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const iteratorPrototype = Object.getPrototypeOf(
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Object.getPrototypeOf([].values()),
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);
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iteratorPrototype.toIterable = function () {
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this[Symbol.iterator] ??= Function.returnThis;
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return this;
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};
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globalThis.Iterator ??= {};
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globalThis.Iterator.from ??= function (object) {
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const toIterable = iteratorPrototype.toIterable;
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const iteratorFactory = object[Symbol.iterator];
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if (typeof iteratorFactory === "function") {
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return toIterable.call(iteratorFactory.call(object));
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}
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// eslint-disable-next-line no-prototype-builtins
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if (iteratorPrototype.isPrototypeOf(object)) {
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return toIterable.call(object);
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}
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if (typeof object.next === "function") {
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return (function* () {
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yield* toIterable.call(object);
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})();
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}
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throw new TypeError(
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"Object is not an iterator, iterable, or an object with a next method",
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);
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};
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/////////////////////////// END ADVENTURE PACK CODE ////////////////////////////"
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`;
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exports[`App can equip single goody: JavaScript Iterator.prototype 1`] = `
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"////////////////////////// BEGIN ADVENTURE PACK CODE ///////////////////////////
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// Adventure Pack commit fake-commit-hash
@@ -3280,6 +3327,79 @@ Function.returnThis = function <T>(this: T): T {
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/////////////////////////// END ADVENTURE PACK CODE ////////////////////////////"
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`;
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exports[`App can equip single goody: TypeScript Iterator.from 1`] = `
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"////////////////////////// BEGIN ADVENTURE PACK CODE ///////////////////////////
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// Adventure Pack commit fake-commit-hash
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// Running at: https://example.com/
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declare global {
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interface FunctionConstructor {
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returnThis<T>(this: T): T;
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}
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interface Iterator<T> {
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toIterable(this: Iterator<T>): IterableIterator<T>;
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}
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interface IteratorConstructor {
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from<T>(
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object: Iterator<T> | Iterable<T> | { next(): IteratorResult<T> },
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): IterableIterator<T>;
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}
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const Iterator: IteratorConstructor;
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}
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Function.returnThis = function <T>(this: T): T {
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return this;
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};
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const iteratorPrototype = Object.getPrototypeOf(
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Object.getPrototypeOf([].values()),
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) as Iterator<unknown, unknown, unknown>;
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iteratorPrototype.toIterable = function <T>(
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this: Iterator<T>,
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): IterableIterator<T> {
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(this as unknown as Record<symbol, unknown>)[Symbol.iterator] ??=
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Function.returnThis;
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return this as unknown as IterableIterator<T>;
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};
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(globalThis as Record<string, unknown>).Iterator ??= {};
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((globalThis as Record<string, unknown>).Iterator as { from: unknown }).from ??=
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function <T>(
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object: Iterator<T> | Iterable<T> | { next(): IteratorResult<T> },
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): IterableIterator<T> {
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const toIterable = iteratorPrototype.toIterable as (
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this: Iterator<T>,
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) => IterableIterator<T>;
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const iteratorFactory = (object as Iterable<T>)[Symbol.iterator];
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if (typeof iteratorFactory === "function") {
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return toIterable.call(iteratorFactory.call(object));
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}
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// eslint-disable-next-line no-prototype-builtins
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if (iteratorPrototype.isPrototypeOf(object)) {
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return toIterable.call(object as Iterator<T>);
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}
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if (typeof (object as Record<string, unknown>).next === "function") {
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return (function* () {
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yield* toIterable.call(object as Iterator<T>);
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})();
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}
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throw new TypeError(
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"Object is not an iterator, iterable, or an object with a next method",
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);
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};
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/////////////////////////// END ADVENTURE PACK CODE ////////////////////////////"
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`;
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exports[`App can equip single goody: TypeScript Iterator.prototype 1`] = `
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"////////////////////////// BEGIN ADVENTURE PACK CODE ///////////////////////////
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// Adventure Pack commit fake-commit-hash

‎workspaces/adventure-pack/src/app/__tests__/__snapshots__/render-test.ts.snap‎

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@@ -800,6 +800,37 @@ exports[`App can render goody: JavaScript Function.returnThis 1`] = `
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};"
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`;
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exports[`App can render goody: JavaScript Iterator.from 1`] = `
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"import "Iterator.prototype";
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import "Iterator.prototype.toIterable";
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globalThis.Iterator ??= {};
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globalThis.Iterator.from ??= function (object) {
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const toIterable = iteratorPrototype.toIterable;
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const iteratorFactory = object[Symbol.iterator];
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if (typeof iteratorFactory === "function") {
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return toIterable.call(iteratorFactory.call(object));
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}
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// eslint-disable-next-line no-prototype-builtins
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if (iteratorPrototype.isPrototypeOf(object)) {
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return toIterable.call(object);
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}
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if (typeof object.next === "function") {
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return (function* () {
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yield* toIterable.call(object);
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})();
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}
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throw new TypeError(
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"Object is not an iterator, iterable, or an object with a next method",
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);
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};"
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`;
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exports[`App can render goody: JavaScript Iterator.prototype 1`] = `
804835
"export const iteratorPrototype = Object.getPrototypeOf(
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Object.getPrototypeOf([].values()),
@@ -1939,6 +1970,52 @@ Function.returnThis = function <T>(this: T): T {
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};"
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`;
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exports[`App can render goody: TypeScript Iterator.from 1`] = `
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"import "Iterator.prototype";
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import "Iterator.prototype.toIterable";
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declare global {
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interface IteratorConstructor {
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from<T>(
1980+
object: Iterator<T> | Iterable<T> | { next(): IteratorResult<T> },
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): IterableIterator<T>;
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}
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const Iterator: IteratorConstructor;
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}
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(globalThis as Record<string, unknown>).Iterator ??= {};
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((globalThis as Record<string, unknown>).Iterator as { from: unknown }).from ??=
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function <T>(
1991+
object: Iterator<T> | Iterable<T> | { next(): IteratorResult<T> },
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): IterableIterator<T> {
1993+
const toIterable = iteratorPrototype.toIterable as (
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this: Iterator<T>,
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) => IterableIterator<T>;
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const iteratorFactory = (object as Iterable<T>)[Symbol.iterator];
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if (typeof iteratorFactory === "function") {
1999+
return toIterable.call(iteratorFactory.call(object));
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}
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// eslint-disable-next-line no-prototype-builtins
2003+
if (iteratorPrototype.isPrototypeOf(object)) {
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return toIterable.call(object as Iterator<T>);
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}
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if (typeof (object as Record<string, unknown>).next === "function") {
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return (function* () {
2009+
yield* toIterable.call(object as Iterator<T>);
2010+
})();
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}
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throw new TypeError(
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"Object is not an iterator, iterable, or an object with a next method",
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);
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};"
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`;
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exports[`App can render goody: TypeScript Iterator.prototype 1`] = `
19432020
"export const iteratorPrototype = Object.getPrototypeOf(
19442021
Object.getPrototypeOf([].values()),

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