jestjs/jest · error · Error

Unexpected input

Error message

Unexpected input

What it means

The terminal throw at the end of stringToBytes, reached when none of the preceding branches return. This happens when input is a string whose trailing characters do not match any known unit (%, kb, k, kib, mb, m, mib, gb, g, gib), or when the regex match fails to capture numericString/trailingChars for a non-numeric-ending input.

Solutions

1. Use a supported unit: kb, kib, mb, mib, gb, gib, or their single-letter forms (k, m, g), or %
2. Strip whitespace and commas before calling stringToBytes
3. If you need a larger unit, pre-convert to gb (e.g. 2tb -> 2048gb)

Example fix

// before
stringToBytes('512tb');

// after
stringToBytes('524288gb');

const SUPPORTED_UNITS = ['%', 'kb', 'kib', 'mb', 'mib', 'gb', 'gib', 'k', 'm', 'g'];
function assertSupportedUnit(input: string): void {
  const match = input.match(/(.*?)([^\d.-]+)$/i);
  const unit = match?.[2]?.toLowerCase();
  if (unit && !SUPPORTED_UNITS.includes(unit)) {
    throw new Error(`Unsupported memory unit '${unit}'. Supported: ${SUPPORTED_UNITS.join(', ')}`);
  }
}

const UNIT_RE = /^(\d+(?:\.\d+)?)(kib|mib|gib|kb|mb|gb|k|m|g|%)$/i;
function isSupportedMemoryString(value: unknown): boolean {
  return typeof value === 'string' && UNIT_RE.test(value.trim());
}

When it happens

Trigger: Passing an unrecognized unit like '512xb', '5tb', or '5tb'; a string like 'abc' where the last char is non-numeric but no valid unit is captured; or input of an unexpected type that bypassed all branches.

Common situations: Typos in memory units; unsupported units (terabytes, bits); copy-pasting values formatted with spaces or commas that break the regex.

Related errors

• For a percentage based memory limit a percentageReference…
• Unexpected numerical input
• Can't find a root directory while resolving a config file…
• "cwd" must be an absolute path. cwd
• Jest: ' ' is not a valid TypeScript configuration loader.

AI-assisted analysis of jestjs/jest@8e6d128e4a (2026-08-10). Data as JSON: /api/errors/a029a0876a121837. Report an issue: GitHub.

Appendix: source

Thrown at packages/jest-config/src/stringToBytes.ts:88

  if (typeof input === 'number') {
    if (input === 0) {
      return 0;
    } else if (input <= 1 && input > 0) {
      if (percentageReference) {
        return Math.floor(input * percentageReference);
      } else {
        throw new Error(
          'For a percentage based memory limit a percentageReference must be supplied',
        );
      }
    } else if (input > 1) {
      return Math.floor(input);
    } else {
      throw new Error('Unexpected numerical input');
    }
  }

  throw new Error('Unexpected input');
}

// https://github.com/import-js/eslint-plugin-import/issues/1590
export default stringToBytes;

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