Create a checksum for assets

createChecksum.js

exports.createChecksum = function(asset, algorithm) {
    const md = MessageDigest.getInstance(algorithm);
    let digest;
    if (asset instanceof ByteArray) {
        digest = md.digest(asset);
    } else if (typeof asset === "string") {
        let fis = new java.io.FileInputStream(asset);
        let dis = new java.security.DigestInputStream(fis, md);
        let buffer = new ByteArray(8192);
        try {
            while (dis.read(buffer) != -1);
        } catch (e) {
            throw new Error("Could not create checksum! " + e);
        } finally {
            buffer = null;
            fis.close();
            dis.close();
        }
        digest = md.digest();
    } else {
        throw new Error("Invalid type! " + typeof asset);
    }

    return algorithm.toLowerCase() + "-" + b16encode(ByteString.wrap(digest));
};