If you want to pick up where you left while working with the previous report, you can load it into the pivot table:
Load your report while embedding WebDataRocks by specifying a path to your report file:
let pivot = new WebDataRocks({
container: "#pivot-container",
toolbar: true,
// Replace this URL with your report file
report: "https://cdn.webdatarocks.com/reports/report.json"
});