an = str => {
  str = `${str}`;
  if (str.length >= 1 && stringIncludes('aeiouAEIOU', str[0])) {
    return `an ${str}`;
  }
  return `a ${str}`;
}
Prepend the correct indefinite article onto a noun, typically a typeof
result, e.g., "an object" vs. "a number"

@param {string} str The noun to prepend
@returns {string} The noun prepended with a/an