maxWord

function isLetter(s) {
    if ((s.charCodeAt(0) >= 65 && s.charCodeAt(0) <= 90) ||
        (s.charCodeAt(0) >= 97 && s.charCodeAt(0) <= 122)) {
        return true;
    } else
        return false;
}

let line = '  rrqwe     wett gggggg ';
//let wordLength = 0;
//let maxWordLength = 0;
let word = "";
let maxWord = "";
for (let i = 0; i < line.length; i++) {

    let isCurrentSymbolLetter = isLetter(line[i]);

    if (isCurrentSymbolLetter) {
        //wordLength++;
        word += line[i];
    }

    let isCurrentSymbolLast = (line.length - 1 == i);

    if (!isCurrentSymbolLetter || isCurrentSymbolLast) {
        if (maxWord.length < word.length) {
            //maxWordLength = wordLength;
            maxWord = word
        }
        //wordLength = 0;
        word = "";
    }
}
console.log(maxWord);