_loadFromTiddler(tiddler) {

    const tObj = utils.getTiddler(tiddler);

    if (!tObj) {

      return;
    }

    const shadowTObj = $tw.wiki.getSubTiddler($tm.path.pluginRoot, this.fullPath) || {};

    // copy object to allow manipulation of the data
    const rawData = $tw.utils.extend({}, shadowTObj.fields, tObj.fields);
    // allow parsers to transform the raw field data
    for (let field in this._fieldMeta) {

      const parser = this._fieldMeta[field].parse;
      const rawVal = rawData[field];

      this[field] = (parser ? parser.call(this, rawVal) : rawVal);
    }

  }
Retrieve all data from the tiddler provided. If a shadow tiddler
with the same id exists, its data is merged during the load
process.

@private