Stan Runge
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Dutch and Korean (explained in English) and English (explained in Dutch) from A1 to C1, with a Hangul level for Korean. Lessons with notes, words and sentences generate multiple-choice, typing, sentence building, cloze, listening and matching exercises. Endless challenges: a seeded daily challenge, sprint, survival, mixed practice, level tests, spaced-repetition reviews and generated drills (numbers, clock times, de/het, plurals, Dutch and Korean conjugation, particles, Hangul reading, irregular verbs). Progress is stored in localStorage with export/import. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
51 lines
1.5 KiB
TypeScript
51 lines
1.5 KiB
TypeScript
export type Rng = () => number;
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/** Small deterministic generator, so a daily challenge is the same all day. */
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export function seeded(seed: number | string): Rng {
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let h = typeof seed === 'number' ? seed >>> 0 : 2166136261;
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if (typeof seed === 'string') {
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for (let i = 0; i < seed.length; i++) h = Math.imul(h ^ seed.charCodeAt(i), 16777619);
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}
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return () => {
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h = (h + 0x6d2b79f5) >>> 0;
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let t = h;
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t = Math.imul(t ^ (t >>> 15), t | 1);
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t ^= t + Math.imul(t ^ (t >>> 7), t | 61);
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return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
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};
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}
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export const int = (rng: Rng, min: number, max: number) =>
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min + Math.floor(rng() * (max - min + 1));
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export const pick = <T>(rng: Rng, list: readonly T[]): T => list[Math.floor(rng() * list.length)];
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export function shuffle<T>(rng: Rng, list: readonly T[]): T[] {
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const copy = [...list];
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for (let i = copy.length - 1; i > 0; i--) {
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const j = Math.floor(rng() * (i + 1));
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[copy[i], copy[j]] = [copy[j], copy[i]];
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}
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return copy;
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}
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/** Up to `count` distinct values from `list` that differ from `exclude` once normalized. */
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export function sample<T>(
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rng: Rng,
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list: readonly T[],
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count: number,
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key: (value: T) => string = String,
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exclude: string[] = []
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): T[] {
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const seen = new Set(exclude.map((value) => value.toLowerCase()));
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const out: T[] = [];
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for (const value of shuffle(rng, list)) {
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if (out.length >= count) break;
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const k = key(value).toLowerCase();
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if (seen.has(k)) continue;
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seen.add(k);
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out.push(value);
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}
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return out;
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}
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