How to use the ripple-address-codec.decodeNodePublic function in ripple-address-codec

function verifySignature(manifest) {
    const sfSequence = '$'
    const sfPublicKey = 'q'
    const sfSigningPubKey = 's'

    // Form manifest
    var sequence_buf = new Buffer(4)
    sequence_buf.writeUInt32BE(manifest.sequence)
    const sequence_bytes = sequence_buf.toJSON().data

    var master_public_bytes = addressCodec.decodeNodePublic(manifest.master_public_key)
    const signature = manifest.master_signature ? manifest.master_signature : manifest.signature
    const signature_bytes = new Buffer(signature, 'hex').toJSON().data

    var manifest_data = new Buffer('MAN\0').toJSON().data
    manifest_data = manifest_data.concat(new Buffer(sfSequence).toJSON().data,
                               sequence_bytes,
                               new Buffer(sfPublicKey).toJSON().data,
                               [master_public_bytes.length],
                               master_public_bytes)

    if (manifest.ephemeral_public_key) {
      const ephemeral_public_bytes = addressCodec.decodeNodePublic(manifest.ephemeral_public_key)
      manifest_data = manifest_data.concat(
        new Buffer(sfSigningPubKey).toJSON().data,
        [ephemeral_public_bytes.length],
        ephemeral_public_bytes)

sequence_buf.writeUInt32BE(manifest.sequence)
    const sequence_bytes = sequence_buf.toJSON().data

    var master_public_bytes = addressCodec.decodeNodePublic(manifest.master_public_key)
    const signature = manifest.master_signature ? manifest.master_signature : manifest.signature
    const signature_bytes = new Buffer(signature, 'hex').toJSON().data

    var manifest_data = new Buffer('MAN\0').toJSON().data
    manifest_data = manifest_data.concat(new Buffer(sfSequence).toJSON().data,
                               sequence_bytes,
                               new Buffer(sfPublicKey).toJSON().data,
                               [master_public_bytes.length],
                               master_public_bytes)

    if (manifest.ephemeral_public_key) {
      const ephemeral_public_bytes = addressCodec.decodeNodePublic(manifest.ephemeral_public_key)
      manifest_data = manifest_data.concat(
        new Buffer(sfSigningPubKey).toJSON().data,
        [ephemeral_public_bytes.length],
        ephemeral_public_bytes)
    }

    master_public_bytes.shift()
    if (!Ed25519.verify(manifest_data, signature_bytes, master_public_bytes)) {
      return false;
    }
    return true;
  };