import assert from 'node:assert/strict';
export function quantity(value) {
  if (!Number.isInteger(value) || value < 1 || value > 20)
    throw new RangeError('Invalid quantity');
  return value;
}
assert.equal(quantity(1), 1);
assert.equal(quantity(20), 20);
assert.throws(() => quantity(0), RangeError);
assert.throws(() => quantity(1.5), RangeError);
console.log('Four boundary assertions passed');