Unicode 大小寫轉換

ToLowerCase.js

/**
 * @param {string} str
 * @return {string}
 */
const toLowerCase = function(str) {
    let strarr = str.split("");
    let samtLetterArr = [];
    let samtLetter = "";
    strarr.forEach(el => {
        let unicode = el.charCodeAt(0);
        let letter = String.fromCharCode(unicode);
        if(unicode <= 90 && unicode >=65){
            letter = String.fromCharCode(unicode + 32);
        }
        samtLetterArr.push(letter);
    });
    samtLetter = samtLetterArr.join('');
    return samtLetter;
};

console.log(toLowerCase('Hello'));
console.log(toLowerCase('here'));
console.log(toLowerCase('LOVELY'));