Number to English Function

number-to-english.js

function numToEng(num) {
  if (num < 1 || num > 999) {
    throw new Error("Number must be between 1 and 999");
  }

  let ones = ["one", "two", "three", "four", "five", "six", "seven", "eight", "nine"];
  let teens = ["eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"];
  let tens = ["ten", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"];

  if (num < 10) return ones[num - 1];
  if (num < 20) return teens[num - 11];
  if (num < 100) {
    return tens[Math.floor(num / 10) - 1] + (num % 10 ? " " + ones[(num % 10) - 1] : "");
  }
  return ones[Math.floor(num / 100) - 1] + " hundred" + (num % 100 ? " " + numToEng(num % 100) : "");
}

Instruction:
Write a function that accepts a positive integer between 0 and 999 inclusive and returns a string representation of that integer written in English.

Notes

• There are no hyphens used (e.g. "thirty five" not "thirty-five").
• The word "and" is not used (e.g. "one hundred one" not "one hundred and one").