function smallestCommons(arr) {

  // Setup

  const [min, max] = arr.sort((a, b) => a - b);

  const numberDivisors = max - min + 1;

  // Largest possible value for SCM

  let upperBound = 1;

  for (let i = min; i <= max; i++) {

    upperBound *= i;

  }

  // Test all multiples of 'max'

  for (let multiple = max; multiple <= upperBound; multiple += max) {

    // Check if every value in range divides 'multiple'

    let divisorCount = 0;

    for (let i = min; i <= max; i++) {

      // Count divisors

      if (multiple % i === 0) {

        divisorCount += 1;

      }

    }

    if (divisorCount === numberDivisors) {

      return multiple;

    }

  }

}

​

smallestCommons([1, 5]);