Convert 32 bytes secp256k1 publicKey into compressed public key

convertSecp256k1PubKeyToCompressed.ts

function determineSignByte(publicKey: string): string {
    
    if(publicKey.length !== 64) {
        throw new Error("required `public key` of length 32");
    }

    const xCoordinate = BigInt("0x" + publicKey);
    return xCoordinate % BigInt(2) === BigInt(0) ? "02" : "03";
}
 
function u8ToHex(arr: Uint8Array): string {
    return Array.from(arr)
      .map(byte => byte.toString(16).padStart(2, '0'))
      .join('');
} 

function convertIntoCompressedPubKey(publicKey: Uint8Array|string): string {

    let pubKeyInHex: string = publicKey as string
    if(typeof publicKey === "object") {
        pubKeyInHex = u8ToHex(publicKey);
    }

    return determineSignByte(pubKeyInHex)+pubKeyInHex;
}

// Example
convertIntoCompressedPubKey("dc6809580a89f0e723ecb1634f06d329252f45ec47c4cadcbc1836fe9da236c5"); // compressed with negative sign(03....)
convertIntoCompressedPubKey("dc3db8e6db9539f6f5aef7865cbc02022eec4b0eb9e57e950b29c6b52c2858c6"); // Positive with positive sign(02.....)