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sync.ts
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sync.ts
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import {
InputOperationsArray,
IterableEngineContext,
UnknownReturnedIterableError
} from "../../engine/context";
import {
drop, every,
filter, FilterFn, find,
flatMap,
forEach, ForEachFn,
map, MapFn,
reduce, ReduceFn,
some,
take,
toArray
} from "../../operations/sync";
import { isIterable } from "../../async-like";
import { TC39AsyncIteratorHelpersFn } from "./async";
export interface TC39IterableHelpersObject<T> extends Iterable<T> {
map?<O>(mapperFn: MapFn<T, O>): TC39IterableHelpersObject<O>;
filter?(filterFn: FilterFn<T>): TC39IterableHelpersObject<T>;
take?(limit: number): TC39IterableHelpersObject<T>;
drop?(limit: number): TC39IterableHelpersObject<T>;
flatMap?<O>(mapperFn: MapFn<T, Iterable<O>>): TC39IterableHelpersObject<O>;
reduce?<A>(reduceFn: ReduceFn<T, A>, initial: A): A;
toArray?(): T[];
forEach?(callbackFn: ForEachFn<T>): void;
some?(filterFn: FilterFn<T>): boolean;
every?(filterFn: FilterFn<T>): boolean;
find?(filterFn: FilterFn<T>): T | undefined;
}
export function assertTC39IteratorHelpersObject<O extends InputOperationsArray, T>(input: unknown): asserts input is (...operations: O) => Omit<IterableEngineContext<O, never | number>, "instance"> & { instance(): TC39IterableHelpersObject<T> } {
type HelperFn = <T = unknown, O = unknown, A extends InputOperationsArray<T, O> = InputOperationsArray<T, O>>(...operations: A) => (Omit<IterableEngineContext<A, never | number>, "instance"> & { instance<T>(input: Iterable<T>): TC39IterableHelpersObject<T> });
function assertFunction(value: unknown): asserts value is HelperFn {
if (typeof value !== "function") throw new Error();
}
assertFunction(input);
const test: HelperFn = input;
function* naturals() {
let i = 0;
while (true) {
yield i;
i += 1;
}
}
const mapNaturalsOps = test(map((value: number) => {
return value * value;
}));
const mapNaturalsResultIterator = mapNaturalsOps.instance(naturals())[Symbol.iterator]();
ok(mapNaturalsResultIterator.next().value === 0); // {value: 0, done: false};
ok(mapNaturalsResultIterator.next().value === 1); // {value: 1, done: false};
ok(mapNaturalsResultIterator.next().value === 4); // {value: 4, done: false};
const filterNaturalsOps = test(filter((value: number) => {
return value % 2 == 0;
}));
const filterNaturalsResultIterator = filterNaturalsOps.instance(naturals())[Symbol.iterator]();
ok(filterNaturalsResultIterator.next().value === 0); // {value: 0, done: false};
ok(filterNaturalsResultIterator.next().value === 2); // {value: 2, done: false};
ok(filterNaturalsResultIterator.next().value === 4); // {value: 4, done: false};
const takeNaturalsOps = test(take(3));
const takeNaturalsResultIterator = takeNaturalsOps.instance(naturals())[Symbol.iterator]();
ok(takeNaturalsResultIterator.next().value === 0); // {value: 0, done: false};
ok(takeNaturalsResultIterator.next().value === 1); // {value: 1, done: false};
ok(takeNaturalsResultIterator.next().value === 2); // {value: 2, done: false};
const takeNaturalsResultDone = takeNaturalsResultIterator.next(); // {value: undefined, done: true};
ok(takeNaturalsResultDone.done === true);
ok(!takeNaturalsResultDone.value);
const dropNaturalsOps = test(drop(3));
const dropNaturalsResultIterator = dropNaturalsOps.instance(naturals())[Symbol.iterator]();
ok(dropNaturalsResultIterator.next().value === 3); // {value: 3, done: false};
ok(dropNaturalsResultIterator.next().value === 4); // {value: 4, done: false};
ok(dropNaturalsResultIterator.next().value === 5); // {value: 5, done: false};
const flatMapOps = test(flatMap((value: string) => value.split(" ")));
const flatMapResultIterator = flatMapOps.instance(["It's Sunny in", "", "California"])[Symbol.iterator]();
ok(flatMapResultIterator.next().value === "It's"); // {value: "It's", done: false};
ok(flatMapResultIterator.next().value === "Sunny"); // {value: "Sunny", done: false};
ok(flatMapResultIterator.next().value === "in"); // {value: "in", done: false};
ok(flatMapResultIterator.next().value === ""); // {value: "", done: false};
ok(flatMapResultIterator.next().value === "California"); // {value: "California", done: false};
const flatMapResultDone = flatMapResultIterator.next(); // {value: undefined, done: true};
ok(flatMapResultDone.done === true);
ok(!flatMapResultDone.value);
const reduceNaturalsOps = test(take(5), reduce((sum: number, value: number) => {
return sum + value;
}, 3));
const reduceNaturalsResultIterable = reduceNaturalsOps.instance(naturals());
const reduceNaturalsResult = getThrownResult(reduceNaturalsResultIterable);
ok(reduceNaturalsResult === 13);
const naturalsArrayOps = test(take(5), toArray());
// toArray is an Iterable so is seen as a valid operation result
const naturalsArrayResult = [...naturalsArrayOps.instance(naturals())];
ok(Array.isArray(naturalsArrayResult));
ok(naturalsArrayResult.length === 5);
ok(naturalsArrayResult[0] === 0);
ok(naturalsArrayResult[1] === 1);
ok(naturalsArrayResult[2] === 2);
ok(naturalsArrayResult[3] === 3);
ok(naturalsArrayResult[4] === 4);
const naturalsArrayResultIterator = naturalsArrayOps.instance(naturals())[Symbol.iterator]();
const naturalsArrayResult0 = naturalsArrayResultIterator.next();
ok(naturalsArrayResult0.value === 0);
const naturalsArrayResult1 = naturalsArrayResultIterator.next();
ok(naturalsArrayResult1.value === 1);
const naturalsArrayResult2 = naturalsArrayResultIterator.next();
ok(naturalsArrayResult2.value === 2);
const naturalsArrayResult3 = naturalsArrayResultIterator.next();
ok(naturalsArrayResult3.value === 3);
const naturalsArrayResult4 = naturalsArrayResultIterator.next();
ok(naturalsArrayResult4.value === 4);
const naturalsArrayResultDone = naturalsArrayResultIterator.next();
ok(naturalsArrayResultDone.done);
const forEachLog: unknown[] = [];
const forEachOps = test<number>(drop(1), take(3), forEach((value) => forEachLog.push(value)));
getThrownResult(forEachOps.instance(naturals()));
ok(forEachLog.join(", ") === "1, 2, 3"); // "1, 2, 3"
const someOps = test<number>(take(4), some(v => v > 1));
ok(getThrownResult(someOps.instance(naturals())) === true);
const someOpsOneTrue = test(take(4), some(v => v === 1));
ok(getThrownResult(someOpsOneTrue.instance(naturals())) === true);
const everyOverOps = test<number>(drop(1), take(4), every(v => v > 1));
ok(getThrownResult(everyOverOps.instance(naturals())) === false); // false, first value is 1
const everyOverEqualOps = test<number>(drop(1), take(4), every(v => v >= 1));
ok(getThrownResult(everyOverEqualOps.instance(naturals())) === true);
const findOps = test<number>(find((value: number) => value > 1));
ok(getThrownResult(findOps.instance(naturals())) === 2);
function getThrownResult(iterable: unknown) {
if (!isIterable(iterable)) return iterable;
try {
return void [...iterable];
} catch (error) {
if (error instanceof UnknownReturnedIterableError) {
return error.value;
}
throw error;
}
}
function ok(value: unknown, message?: string): asserts value {
if (!value) {
throw new Error(message);
}
}
}