17 lines
630 B
TypeScript
17 lines
630 B
TypeScript
/** pick up to random N elements from array.
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* just shuffle it if N is unspecified or greater than the length of the array.
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* the original array remains unmodified. */
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export function sample<T>(arr: T[], n: number = arr.length): T[] {
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if (n > arr.length) return sample(arr, arr.length);
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const copy = [...arr];
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for (let i = 0; i < n; i++) {
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const j = i + Math.floor(Math.random() * (copy.length - i));
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[copy[i], copy[j]] = [copy[j] as T, copy[i] as T];
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}
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return copy.slice(0, n);
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}
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/** sleep for N milliseconds */
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export const sleep = (msec: number) =>
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new Promise((resolve) => setTimeout(resolve, msec));
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