getMatchingVisibleMetas(type) {
    const metas = this.chart.getSortedVisibleDatasetMetas();
    const axisID = this.axis + 'AxisID';
    const result = [];
    let i, ilen;

    for (i = 0, ilen = metas.length; i < ilen; ++i) {
      const meta = metas[i];
      if (meta[axisID] === this.id && (!type || meta.type === type)) {
        result.push(meta);
      }
    }
    return result;
  }
Returns visible dataset metas that are attached to this scale
@param {string} [type] - if specified, also filter by dataset type
@return {object[]}