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import * as iter from './iterator.js';
import { beforeEach, expect, test, describe, it, vi } from 'vitest';
describe('map', async () => {
it('applies the mapping function to each item', async () => {
const seq = Iterator.from([1, 2, 3, 5, 8]);
const mapped = iter.map(seq, (x) => 2 * x);
expect(Array.from(mapped)).toStrictEqual([2, 4, 6, 10, 16]);
});
});
describe('reduce', async () => {
it('accumulates results and returns them', async () => {
const seq = Iterator.from([1, 2, 3, 4]);
const reduced = iter.reduce(seq, (sum, x) => sum + x, 0);
// Good ol' triangle numbers.
expect(reduced).toStrictEqual(10);
});
});
describe('chunkBy', async () => {
describe('with trivial operand functions', async () => {
it('yields nothing for an empty input', async () => {
const chunks = iter.chunkBy(
[],
(val) => val,
(last, next) => last === next
);
expect(Array.from(chunks)).toStrictEqual([]);
});
it('yields one chunk input for a singleton input', async () => {
const chunks = iter.chunkBy(
[37],
(val) => val,
(last, next) => last === next
);
expect(Array.from(chunks)).toStrictEqual([{ key: 37, chunk: [37] }]);
});
it('yields chunks of successive inputs', async () => {
const chunks = iter.chunkBy(
[37, 37, 28, 37],
(val) => val,
(last, next) => last === next
);
expect(Array.from(chunks)).toStrictEqual([
{ key: 37, chunk: [37, 37] },
{ key: 28, chunk: [28] },
{
key: 37,
chunk: [37]
}
]);
});
});
describe('with a complex key function', async () => {
it('returns the key with each chunk', async () => {
const chunks = iter.chunkBy(
[37, 37, 28, 37],
(val) => val >> 1,
(last, next) => last === next
);
expect(Array.from(chunks)).toStrictEqual([
{ key: 18, chunk: [37, 37] },
{ key: 14, chunk: [28] },
{ key: 18, chunk: [37] }
]);
});
});
describe('with a complex coalesce function', async () => {
it('continues the chunk when specified', async () => {
const chunks = iter.chunkBy(
[36, 37, 28, 29, 30, 38],
(val) => val,
(last, next) => last + 1 === next
);
expect(Array.from(chunks)).toStrictEqual([
{ key: 37, chunk: [36, 37] },
{ key: 30, chunk: [28, 29, 30] },
{ key: 38, chunk: [38] }
]);
});
});
});
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