Problem 10. Number as Words / switch

// Write a program that converts a number in the range [0…999] to words,
// corresponding to the English pronunciation.

// Examples:
// num  word:
// 0    Zero
// 9    Nine
// 10   Ten
// 12   Twelve
// 19   Nineteen
// 25   Twenty five
// 98   Ninety eight
// 98   Ninety eight
// 273  Two hundred and seventy three
// 400  Four hundred
// 501  Five hundred and one
// 617  Six hundred and seventeen
// 711  Seven hundred and eleven
// 999  Nine hundred and ninety nine
let input = ['211'];

let print = this.print || console.log;
let gets = this.gets || ((arr, index) => () => arr[index++])(input, 0);

let stringInput = gets();
let resultString = '';

if (stringInput.length === 3) {
    const firstDigitUnique = +stringInput[0];
    const secondDigit = +stringInput[1];
    const thirdDigit = +stringInput[2];

    switch (firstDigitUnique) {
        case 1:
            resultString += 'one hundred';
            break;
        case 2:
            resultString += 'two hundred';
            break;
        case 3:
            resultString += 'three hundred';
            break;
        case 4:
            resultString += 'four hundred';
            break;
        case 5:
            resultString += 'five hundred';
            break;
        case 6:
            resultString += 'six hundred';
            break;
        case 7:
            resultString += 'seven hundred';
            break;
        case 8:
            resultString += 'eight hundred';
            break;
        case 9:
            resultString += 'nine hundred';
            break;
    }

    if (secondDigit === 0 && thirdDigit === 0) {
        stringInput = '';
    } else {
        resultString += ' and';
        stringInput = secondDigit + '' + thirdDigit;

    }
}

if (stringInput.length === 2) {
    const number = +stringInput;

    if (number < 20) {
        switch (number) {
            case 1:
                resultString += ' one';
                break;
            case 2:
                resultString += ' two';
                break;
            case 3:
                resultString += ' three';
                break;
            case 4:
                resultString += ' four';
                break;
            case 5:
                resultString += ' five';
                break;
            case 6:
                resultString += ' six';
                break;
            case 7:
                resultString += ' seven';
                break;
            case 8:
                resultString += ' eight';
                break;
            case 9:
                resultString += ' nine';
                break;
            case 10:
                resultString += ' ten';
                break;
            case 11:
                resultString += ' eleven';
                break;
            case 12:
                resultString += ' twelve';
                break;
            case 13:
                resultString += ' thirteen';
                break;
            case 14:
                resultString += ' fourteen';
                break;
            case 15:
                resultString += ' fifteen';
                break;
            case 16:
                resultString += ' sixteen';
                break;
            case 17:
                resultString += ' seventeen';
                break;
            case 18:
                resultString += ' eighteen';
                break;
            case 19:
                resultString += ' nineteen';
                break;
        }
    } else {
        const firstDigit = +stringInput[0];
        const secondDigit = +stringInput[1];

        switch (firstDigit) {
            case 2:
                resultString += ' twenty';
                break;
            case 3:
                resultString += ' thirty';
                break;
            case 4:
                resultString += ' fourty';
                break;
            case 5:
                resultString += ' fifty';
                break;
            case 6:
                resultString += ' sixty';
                break;
            case 7:
                resultString += ' seventy';
                break;
            case 8:
                resultString += ' eighty';
                break;
            case 9:
                resultString += ' ninety';
                break;
        }

        if (secondDigit === 0) {
            stringInput = '';
        } else {
            stringInput = '' + secondDigit;
        }
    }
}
if (stringInput.length === 1) {
    const number = +stringInput;
    switch (number) {
        case 0:
            resultString += ' zero';
            break;
        case 1:
            resultString += ' one';
            break;
        case 2:
            resultString += ' two';
            break;
        case 3:
            resultString += ' three';
            break;
        case 4:
            resultString += ' four';
            break;
        case 5:
            resultString += ' five';
            break;
        case 6:
            resultString += ' six';
            break;
        case 7:
            resultString += ' seven';
            break;
        case 8:
            resultString += ' eight';
            break;
        case 9:
            resultString += ' nine';
            break;
    }
}

resultString = resultString.trim();
const firstLetter = resultString.charAt(0).toUpperCase();
resultString = firstLetter + resultString.substring(1);

console.log(resultString);