_determineDifference(firstSet, secondSet) {
    const arrayDiff = function (firstArr, secondArr) {
      const result = [];

      for (let i = 0; i < firstArr.length; i++) {
        const value = firstArr[i];
        if (secondArr.indexOf(value) === -1) {
          result.push(value);
        }
      }

      return result;
    };

    return {
      nodes: arrayDiff(firstSet.nodes, secondSet.nodes),
      edges: arrayDiff(firstSet.edges, secondSet.edges),
    };
  }
Remove all node and edge id's from the first set that are present in the second one.
@param {{nodes: Array.<Node>, edges: Array.<vis.Edge>}} firstSet
@param {{nodes: Array.<Node>, edges: Array.<vis.Edge>}} secondSet
@returns {{nodes: Array.<Node>, edges: Array.<vis.Edge>}}
@private