I want to compute the merkle root for transactions in a given template block - bitcoind:getblocktemplate().

I understand the merkle root is a hash of all the transactions in a block from the last up to the coinbase transaction, but this is currently way above my pay grade and the documentation I can find for this process is abstract and sketchy at best.

Has anyone done this in JavaScript or know of a resource that could be helpful?

Thanks in advance.

client.getBlockTemplate( function(error, template) {
    if (error) return console.log(error);

    // SETUP MINING
    nonce=0;
    const block = {
        version: template.version
        ,previousblockhash: template.previousblockhash
        ,merkleroot: calculateMerkleRoot(template)
        ,time: template.mintime
        ,bits: template.bits
    }           

    // START MINER
    miner(block,nonce);
});