vitest-dev/vitest · error · Error

bitLength is required

Error message

bitLength is required

What it means

Thrown by the example profiling helper getPrimeNumbers() in examples/profiling when its bitLength argument is falsy. This is demo/benchmark code (not shipped Vitest API) that generates a random prime BigInt of a given bit length. The guard rejects 0, NaN, undefined, null, and '' because the algorithm needs a concrete positive bit length to build the binary string.

Source

Thrown at examples/profiling/src/prime-number.ts:7

/* eslint-disable unicorn/no-new-array */

const store: bigint[] = []

export default function getPrimeNumber(bitLength: number): bigint {
  if (!bitLength) {
    throw new Error('bitLength is required')
  }

  const number = randomBigInt(bitLength)

  if (isPrimeNumber(number) && !store.includes(number)) {
    store.push(number)

    return number
  }

  return getPrimeNumber(bitLength)
}

/**
 * Generate random `BigInt` with given bit length
 * e.g. randomBigInt(8) -> 153n (1001 1001)
 */
function randomBigInt(bitLength: number): bigint {

View on GitHub (pinned to d568f8ce37)

Solutions

1. Pass a positive integer bit length, e.g. getPrimeNumbers(8) or getPrimeNumbers(256).
2. If bitLength comes from config, validate/coerce it before calling: const bits = Number(process.env.BITS) || 256.
3. Replace the truthy guard with an explicit range check if you control the file: if (!Number.isInteger(bitLength) || bitLength <= 0).

Example fix

// before
getPrimeNumbers(0)
getPrimeNumbers(Number(process.env.BITS)) // BITS unset -> NaN

// after
getPrimeNumbers(256)
const bits = Number.parseInt(process.env.BITS ?? '256', 10)
if (!Number.isInteger(bits) || bits <= 0) throw new Error('BITS must be a positive integer')
getPrimeNumbers(bits)

function assertBitLength(bitLength: number): void {
  if (!Number.isInteger(bitLength) || bitLength <= 0) {
    throw new TypeError(`bitLength must be a positive integer, got ${bitLength}`)
  }
}
assertBitLength(bits)
getPrimeNumbers(bits)

function isValidBitLength(v: unknown): v is number {
  return typeof v === 'number' && Number.isInteger(v) && v > 0
}

When it happens

Trigger: Calling getPrimeNumbers(0), getPrimeNumbers(undefined), getPrimeNumbers(NaN), or calling it with a value read from an unset config/env variable that defaulted to 0. The truthy check `if (!bitLength)` treats 0 as invalid even though 0 is a valid number type.

Common situations: Running the profiling example with a CLI flag that was not parsed, a default config value of 0, or a destructured property that was undefined. Also hit when a caller assumes 0 means 'pick a default'.

Related errors

• Negative numbers are not supported
• Cannot use two functions as arguments. Please use the second
• Cannot compare screenshots without a test path
• `resolveOptions` has to be used in a test file
• Invalid command name "${name}". Only alphanumeric characters

AI-assisted analysis of vitest-dev/vitest@d568f8ce37 (2026-08-03). Data as JSON: /data/errors/d7a5db5d390c2a4d.json. Report an issue: GitHub.