phaserjs/phaser · error · Error

Range Error: Values outside acceptable range

Error message

Range Error: Values outside acceptable range

What it means

Thrown by Phaser.Utils.Array.SafeRange ONLY when its fourth argument throwError is truthy; by default it returns false instead of throwing. A range is unsafe when startIndex < 0, startIndex >= array.length, startIndex >= endIndex, or endIndex > array.length. SafeRange is a pre-check helper used by other array utilities (e.g. range-based remove/slice wrappers) that opt into hard failures via the throwError flag.

Source

Thrown at src/utils/array/SafeRange.js:34

 * @param {array} array - The array to check.
 * @param {number} startIndex - The inclusive start index of the range. Must be zero or greater and less than `endIndex`.
 * @param {number} endIndex - The exclusive end index of the range. Must be greater than `startIndex` and no greater than the array length.
 * @param {boolean} [throwError=false] - If `true`, a `Range Error` is thrown when the range is out of bounds instead of returning `false`.
 *
 * @return {boolean} True if the range is safe, otherwise false.
 */
var SafeRange = function (array, startIndex, endIndex, throwError)
{
    var len = array.length;

    if (startIndex < 0 ||
        startIndex >= len ||
        startIndex >= endIndex ||
        endIndex > len)
    {
        if (throwError)
        {
            throw new Error('Range Error: Values outside acceptable range');
        }

        return false;
    }
    else
    {
        return true;
    }
};

module.exports = SafeRange;

View on GitHub (pinned to 41be1e462b)

Solutions

1. Normalize before calling: clamp start to [0, len-1], set end = Math.min(end, len), and ensure start < end.
2. If you only want a boolean check, omit the throwError argument (defaults to false) and branch on the return value.
3. Use Array.prototype.slice for read-only sub-arrays; it tolerates out-of-range indices without throwing.
4. Validate page math: `end = Math.min(start + pageSize, arr.length);`.

Example fix

// before
Phaser.Utils.Array.SafeRange(arr, start, start + pageSize, true);

// after
var end = Math.min(start + pageSize, arr.length);
if (start < 0) start = 0;
if (start < end) Phaser.Utils.Array.SafeRange(arr, start, end, true);

function safeRangeOrClamp(arr, start, end, throwError) {
  var len = arr.length;
  if (start < 0) start = 0;
  if (end > len) end = len;
  if (start >= end) return throwError ? false : false;
  return Phaser.Utils.Array.SafeRange(arr, start, end, throwError);
}

function isValidRange(arr, start, end) {
  return start >= 0 && start < arr.length && start < end && end <= arr.length;
}

try {
  Phaser.Utils.Array.SafeRange(arr, start, end, true);
} catch (e) {
  if (e.message === 'Range Error: Values outside acceptable range') {
    end = Math.min(end, arr.length);
    start = Math.max(0, Math.min(start, end - 1));
  } else { throw e; }
}

When it happens

Trigger: Calling SafeRange(arr, start, end, true) with an invalid range, OR calling a higher-level Phaser array function that internally passes throwError=true. Off-by-one where endIndex is set to array.length+1, or startIndex equals endIndex (empty range, rejected because start must be < end). Passing start > end by accident.

Common situations: Pagination logic that computes start/end from page/size and overruns on the last page. Slicing a sub-array with endIndex derived from a search that returned -1 (then end becomes large). Reacting to a UI selection range where start/end can be equal or inverted. Calling Phaser.Utils.Array.RemoveBetween or similar that delegates to SafeRange with throwError enabled.

Related errors

• Supplied index out of bounds
• Index out of bounds
• Supplied items must be elements of the same array
• Supplied items must be elements of the same array
• Supplied items must be elements of the same array

AI-assisted analysis of phaserjs/phaser@41be1e462b (2026-08-13). Data as JSON: /api/errors/6164d48e63f37945. Report an issue: GitHub.