TheAlgorithms/JavaScript · error · Error

Invalid input

Error message

Invalid input

What it means

Thrown by `problem35(n)` (Project Euler #35, circular primes) when `n < 2`. The function calls `sieveOfEratosthenes(n)` which needs at least 2 to produce primes, so smaller bounds are rejected. The message is generic. Non-number inputs bypass the guard.

Source

Thrown at Project-Euler/Problem035.js:16

/**
 * Problem 35 - Circular primes
 *
 * @see {@link https://projecteuler.net/problem=35}
 *
 * The number, 197, is called a circular prime because all rotations of the digits: 197, 971, and 719, are themselves prime.
 * There are thirteen such primes below 100: 2, 3, 5, 7, 11, 13, 17, 31, 37, 71, 73, 79, and 97.
 * How many circular primes are there below one million?
 *
 * @author ddaniel27
 */
import { sieveOfEratosthenes } from '../Maths/SieveOfEratosthenes'

function problem35(n) {
  if (n < 2) {
    throw new Error('Invalid input')
  }
  // Get a list of primes without 0, 2, 4, 5, 6, 8; this discards the circular primes 2 & 5
  const list = sieveOfEratosthenes(n).filter(
    (prime) => !prime.toString().match(/[024568]/)
  )

  const result = list.filter((number, _idx, arr) => {
    const str = String(number)
    for (let i = 0; i < str.length; i++) {
      // Get all rotations of the number
      const rotation = str.slice(i) + str.slice(0, i)
      if (!arr.includes(Number(rotation))) {
        // Check if the rotation is prime
        return false
      }
    }
    return true // If all rotations are prime, then the number is circular prime
  })

View on GitHub (pinned to 5c39e87a9a)

Solutions

1. Validate `n >= 2` and is a finite integer upstream.
2. Coerce with `Number(n)` so string/undefined inputs are caught.
3. Pick a sensible default (e.g. 1000000) when the field is missing.

Example fix

// before
problem35(bound) // bound could be 1

// after
const n = Number(bound)
if (!Number.isInteger(n) || n < 2) throw new RangeError('n must be an integer >= 2')
problem35(n)

const n = Number(bound)
if (!Number.isInteger(n) || n < 2) {
  throw new RangeError('n must be an integer >= 2')
}
problem35(n)

const isIntAtLeast2 = (x) => typeof x === 'number' && Number.isInteger(x) && x >= 2

When it happens

Trigger: Call `problem35(0)`, `problem35(1)`, `problem35(-10)`. `n = 2` passes and the sieve returns [2] (then filtered out by the digit regex).

Common situations: Defaulting a 'primes below N' field to 0 or 1, off-by-one boundary confusion, or a request param parsed as 1.

Related errors

• Invalid Input
• No natural numbers exist below 1
• Fibonacci sequence limit can't be less than 1
• Please provide number greater that 1
• Invalid Input

AI-assisted analysis of TheAlgorithms/JavaScript@5c39e87a9a (2026-08-13). Data as JSON: /api/errors/b3f14e1378c16885. Report an issue: GitHub.