Get combinations of array elements

combinations.ts

export function* getCombinations<T>(arr: T[], size: number): Generator<T[]> {
  if (size < 1) {
    throw new Error('Combination size must be at least 1')
  }

  if (arr.length === 0) {
    yield []
  } else if (size === 1) {
    for (const el of arr) {
      yield [el]
    }
  } else {
    const limit = arr.length - size + 1
    for (let i = 0; i < limit; i++) {
      for (const result of getCombinations(arr.slice(i + 1), size - 1)) {
        yield [arr[i], ...result]
      }
    }
  }
}

export function* getVariableCombinations<T>(arr: T[], min: number, max: number) {
  for (let size = min; size <= max; size++) {
    yield* getCombinations(arr, size)
  }
}