makeNode(tiddler, protoNode) {

    const tObj = utils.getTiddler(tiddler);

    if (!tObj || utils.isSystemOrDraft(tObj)) return;

    // merge(!) so later node manipulations do not affect other nodes
    const node = utils.merge({}, protoNode);

    // note: assignId() will not assign an id if the tiddler already has one
    node.id = this.assignId(tObj);

    // backreference to tiddler;
    // https://github.com/felixhayashi/TW5-TiddlyMap/issues/304
    node.tRef = tObj.fields.title;

    // add label
    node.label = this.makeLabel(tObj);

    return node;

  }
Gets a Node representation for a tiddler.

@param {Tiddler} tiddler - the tiddler to represent as node
@param {Object} protoNode - default node properties

@return {Node|void}