camelize.js

let str0 = "The gods have yet to make a man who lacks the patience for absolute power"; // normal string
let str1 = "Half       BLOOD   pRINCE"; // normal string with extra spaces

let str2 = "i_AM_IRON_man"; // snake case
let str3 = "tom-------mARVolo-------Riddle"; // hyphen
let str4 = "Spiderman---FAR    frOM______home"; // mix of all

let str5 = "AManHasNoName"; // somewhat camelCase
let str6 = "godOfThunder "; // already camelCase

let str7 = "undefined null NaN "; // string contains unexpected words
let str8 = 123; // not a string
let str9 = "123 456 str a987BOY"; // string with numbers
let str10 = "--a__b      c"; // string starting with symbols

// Half       BLOOD   pRINCE  ->  halfBloodPrince
// tom-------mARVolo-------Riddle  -> tomMarvoloRiddle
function camelCase(str) {
    if (!str || Number(str)) return str;

    const strSymbolsRemoved = str.replace(/-/g, " ").replace(/_/g, " ");
    const strSplittedBySpace = strSymbolsRemoved.split(" ");
    const extraSpaceRemoved = strSplittedBySpace.filter(item => item !== "");

    if (extraSpaceRemoved.length === 1) {
        const item = extraSpaceRemoved[0];
        return item[0].toLowerCase() + item.slice(1);
    } else {
        const res = extraSpaceRemoved.reduce((acc, item, idx) => {
            const ans = (idx === 0 ? item[0].toLowerCase() : item[0].toUpperCase()) + item.slice(1).toLowerCase();
            return acc + ans;
        }, "");

        return res;
    }
}

// console.log("str0", camelCase(str0));
// console.log("str1", camelCase(str1));
// console.log("str2", camelCase(str2));
// console.log("str3", camelCase(str3));
// console.log("str4", camelCase(str4));
// console.log("str5", camelCase(str5));
// console.log("str6", camelCase(str6));
// console.log("str7", camelCase(str7));
// console.log("str8", camelCase(str8));
// console.log("str9", camelCase(str9));
// console.log("str10", camelCase(str10));




let obj = {
    [str0]: "1",
    [str1]: [
        { [str2]: 2 },
        3,
        {
            [str3]: "4",
            [str4]: [
                { [str5]: 5 }
            ]
        },
        ["6", 7]
    ],
    [str6]: {
        [str7]: {
            [str8]: 8,
            [str9]: {
                [str10]: "9"
            }
        }
    },
    5: "10"
};

const obj2 = [
    { i_d: 1 },
    { i_d: 2 },
    { i_d: 3 },
    "yo",
    {
        o_ne: "1",
        t_wo: "2",
        th_ree: [
            { i_d: 1 },
            { i_d: 2 },
        ]
    },
    ["sa", "a"]
]

let obj3 = [1, 2, 3];

let obj4 = {
    0: 0,
    1: 1,
    2: 2,
    3: 3
}

function camelizeObject(obj) {
    let newObj;
    if (typeof obj === "object") {
        newObj = {};
        if (Array.isArray(obj)) newObj = [];
    } else {
        return obj;
    }

    Object.keys(obj).forEach((key) => {
        const val = obj[key];
        const camelKey = camelCase(key);
        if (typeof val === "object") {
            newObj[camelKey] = camelizeObject(val);
        } else {
            newObj[camelKey] = val;
        }
    });

    return newObj;
}

const res = camelizeObject(obj4);
console.log("obj", (obj4))
console.log("res", (res))