sampleWithReplacement

1/**
2 * Returns a new array with a specified number of random elements,
3 * allowing duplicates (sampling with replacement).
4 *
5 * @param arr - The input array to sample from.
6 * @param count - The number of elements to sample.
7 * @returns A new array with randomly selected elements (duplicates allowed).
8 */
9export function sampleWithReplacement<T>(arr: T[], count: number): T[] {
10  const result: T[] = [];
11
12  for (let i = 0; i < count; i++) {
13    const index = Math.floor(Math.random() * arr.length);
14    result.push(arr[index]);
15  }
16
17  return result;
18}

1test('sampleWithReplacement returns correct count', () => {
2  const result = sampleWithReplacement([1, 2, 3], 5);
3  expect(result.length).toBe(5);
4});
5
6test('sampleWithReplacement allows duplicates', () => {
7  const input = ['a'];
8  const result = sampleWithReplacement(input, 3);
9  expect(result).toEqual(['a', 'a', 'a']);
10});
11
12test('sampleWithReplacement does not include elements outside the input', () => {
13  const input = [10, 20, 30];
14  const result = sampleWithReplacement(input, 100);
15  result.forEach(val => expect(input).toContain(val));
16});