index.js

// A sentence S is given, composed of words separated by spaces.Each word consists of lowercase and uppercase letters only.

// We would like to convert the sentence to "Goat Latin"(a made - up language similar to Pig Latin.)

// The rules of Goat Latin are as follows:

// If a word begins with a vowel(a, e, i, o, or u), append "ma" to the end of the word.
// For example, the word 'apple' becomes 'applema'.

// If a word begins with a consonant(i.e.not a vowel), remove the first letter and append it to the end, then add "ma".
// For example, the word "goat" becomes "oatgma".

// Add one letter 'a' to the end of each word per its word index in the sentence, starting with 1.
// For example, the first word gets "a" added to the end, the second word gets "aa" added to the end and so on.
// Return the final sentence representing the conversion from S to Goat Latin.



//     Example 1:

// Input: "I speak Goat Latin"
// Output: "Imaa peaksmaaa oatGmaaaa atinLmaaaaa"
// Example 2:

// Input: "The quick brown fox jumped over the lazy dog"
// Output: "heTmaa uickqmaaa rownbmaaaa oxfmaaaaa umpedjmaaaaaa overmaaaaaaa hetmaaaaaaaa azylmaaaaaaaaa ogdmaaaaaaaaaa"


// Notes:

// S contains only uppercase, lowercase and spaces.Exactly one space between each word.
// 1 <= S.length <= 150.

//Solution

const toGoatLatin = (S) => {
    const vowel = ['a', 'e', 'i', 'o', 'u'], splited = S.split(' ');

    return splited.map((w, i) => {
        const firstLet = w[0].toLocaleLowerCase();
        const repeatA = 'a'.repeat(i + 1);

        if (vowel.indexOf(firstLet) > -1) {
            return w + 'ma' + repeatA
        } else {
            return w.slice(1) + w[0] + 'ma' + repeatA
        }
    }).join(' ')
};