TheAlgorithms/JavaScript · error · Error

Dimension must be positive

Error message

Dimension must be positive

What it means

Thrown by `problem28(dim)` when `dim < 1`, AFTER the oddness check has passed. So this fires for negative odd numbers (-1, -3, ...) and for `dim = 0` is impossible (0 is even, caught earlier). Note that NaN bypasses both checks because `NaN < 1` is false.

Source

Thrown at Project-Euler/Problem028.js:25

 *
 * 21 22 23 24 25
 * 20 07 08 09 10
 * 19 06 01 02 11
 * 18 05 04 03 12
 * 17 16 15 14 13
 *
 * It can be verified that the sum of the numbers on the diagonals is 101.
 * What is the sum of the numbers on the diagonals in a 1001 by 1001 spiral formed in the same way?
 *
 * @author ddaniel27
 */

function problem28(dim) {
  if (dim % 2 === 0) {
    throw new Error('Dimension must be odd')
  }
  if (dim < 1) {
    throw new Error('Dimension must be positive')
  }

  let result = 1
  for (let i = 3; i <= dim; i += 2) {
    /**
     * Adding more dimensions to the matrix, we will find at the top-right corner the follow sequence:
     * 01, 09, 25, 49, 81, 121, 169, ...
     * So this can be expressed as:
     * i^2, where i is all odd numbers
     *
     * Also, we can know which numbers are in each corner dimension
     * Just develop the sequence counter clockwise from top-right corner like this:
     * First corner: i^2
     * Second corner: i^2 - (i - 1) | The "i - 1" is the distance between corners in each dimension
     * Third corner: i^2 - 2 * (i - 1)
     * Fourth corner: i^2 - 3 * (i - 1)
     *
     * Doing the sum of each corner and simplifying, we found that the result for each dimension is:

View on GitHub (pinned to 5c39e87a9a)

Solutions

1. Validate `dim >= 1` (and odd) in one upstream check.
2. Reject negative inputs at the form/config layer.
3. Guard NaN explicitly - the current check lets it through.

Example fix

// before
problem28(computedDim) // could be -1

// after
const d = Number(computedDim)
if (!Number.isFinite(d) || d < 1 || d % 2 === 0) throw new RangeError('dim must be a positive odd integer')
problem28(d)

const d = Number(dim)
if (!Number.isFinite(d) || d < 1) {
  throw new RangeError('dim must be a positive finite number')
}
problem28(d)

const isPositiveFinite = (x) => typeof x === 'number' && Number.isFinite(x) && x >= 1

When it happens

Trigger: Call `problem28(-1)`, `problem28(-3)`, `problem28(-7)`. Zero and negative even numbers hit the 'must be odd' branch first.

Common situations: Sign errors in computed dimensions, defensive defaults of -1 meaning 'unset', or arithmetic that produced a negative size.

Related errors

• The ${noName} only accepts positive values
• No natural numbers exist below 1
• Fibonacci sequence limit can't be less than 1
• Invalid Input
• Please provide number greater that 1

AI-assisted analysis of TheAlgorithms/JavaScript@5c39e87a9a (2026-08-13). Data as JSON: /api/errors/7d80d10ffc62b09f. Report an issue: GitHub.