TheAlgorithms/JavaScript · error · RangeError

Subarray size k must be between 1 and the length of the arra

Error message

Subarray size k must be between 1 and the length of the array

What it means

Thrown as a RangeError by maxSumSubarrayFixed() when k is greater than the array length or less than 1. The sliding window needs exactly k elements to form a window, so k must be a positive integer no larger than the array. The guard is deliberately a RangeError (not TypeError) because the value type is fine but its magnitude is wrong.

Source

Thrown at Sliding-Windows/MaxSumSubarrayFixed.js:11

/**
 * Function to find the maximum sum of a subarray of fixed size k.
 *
 * @param {number[]} arr - The input array of numbers.
 * @param {number} k - The fixed size of the subarray.
 * @returns {number} - The maximum sum of any subarray of size k.
 * @throws {RangeError} - If k is larger than the array length or less than 1.
 */
export function maxSumSubarrayFixed(arr, k) {
  if (k > arr.length || k < 1) {
    throw new RangeError(
      'Subarray size k must be between 1 and the length of the array'
    )
  }
  let maxSum = 0
  let windowSum = 0
  for (let i = 0; i < k; i++) {
    windowSum += arr[i]
  }
  maxSum = windowSum
  for (let i = k; i < arr.length; i++) {
    windowSum += arr[i] - arr[i - k]
    maxSum = Math.max(maxSum, windowSum)
  }
  return maxSum
}

View on GitHub (pinned to 5c39e87a9a)

Solutions

1. Clamp k: const safeK = Math.min(k, arr.length) and ensure safeK >= 1 before calling.
2. Skip the call for arrays shorter than your desired window.
3. Validate user-supplied window sizes at the input boundary.

Example fix

// before
const best = maxSumSubarrayFixed(arr, windowSize)

// after
const safeK = Math.max(1, Math.min(windowSize, arr.length))
const best = arr.length >= safeK ? maxSumSubarrayFixed(arr, safeK) : 0

function safeMaxSumSubarrayFixed(arr, k) {
  if (!Array.isArray(arr) || arr.length === 0) {
    throw new TypeError('arr must be a non-empty array')
  }
  if (!Number.isInteger(k) || k < 1 || k > arr.length) {
    throw new RangeError(`k must be in [1, ${arr.length}]`)
  }
  return maxSumSubarrayFixed(arr, k)
}

function isValidWindow(arr, k) {
  return Array.isArray(arr) && arr.length > 0 && Number.isInteger(k) && k >= 1 && k <= arr.length
}

try {
  maxSumSubarrayFixed(arr, k)
} catch (e) {
  if (e instanceof RangeError) {
    return maxSumSubarrayFixed(arr, Math.min(Math.max(1, k), arr.length))
  }
  throw e
}

When it happens

Trigger: Calling maxSumSubarrayFixed([1,2,3], 5), maxSumSubarrayFixed([1,2,3], 0), maxSumSubarrayFixed([], 1), or maxSumSubarrayFixed([1,2], -1). Also when k is derived from user input that was not sanitized.

Common situations: Computing window size from a ratio that exceeds array length; passing k=0 as a 'no window' sentinel; empty arrays after filtering where k was sized for the original array.

Related errors

• Grid must be a non-empty array
• LFUCache ERROR: The Capacity is 0
• Both keyword and message must be specified
• Invalid keyword!
• Input is not a valid RGB color.

AI-assisted analysis of TheAlgorithms/JavaScript@5c39e87a9a (2026-08-13). Data as JSON: /api/errors/5e826f65f5186999. Report an issue: GitHub.