Kata

This is the Part II of English words to numbers (my very first kata on CodeWars ☺). But this time we shall support up to "Nine hundred and ninety-nine vigintillion" 999x1063 (Check Names of large numbers for names of large numbers with their corresponding value). We shall be returning strings or NaN if the input doesn't evaluate to a valid number.

NOTE: we are using short scale i.e million is 10⁶ and billion is 10⁹.

Rules

1. Empty string should return "0"
2. Should support up to ± 999x1063
3. A string equivalent of the word passed is returned e.g "one" => "1"
4. No trailing zeros i.e. zero point zero zero one zero => "0.001" NOT "0.0010"
5. If word starts with negative, "-" should be added to the string E.g. "negative five" => "-5"
6. Should work with decimals. E.g. "negative twenty three point two three seven" => "-23.237"
7. Any word that does not evaluate to a number should return NaN E.g. "thirty point ninteen" => NaN. (i.e. It should have been thirty point one nine)
8. Words like one million three billion should return NaN (billion doesn't come after million).
9. Words between 21 and 99 might be hypened E.g. twenty-one, fifty-seven, etc