https://lahioluvut.fi/highcharts-9.3.1/custom/reset.js

1var HCDefaults = $.extend(true, {}, Highcharts.getOptions(), {});
2
3function ResetHighchartsOptions() {
4    // Fortunately, Highcharts returns the reference to defaultOptions itself
5    // We can manipulate this and delete all the properties
6    var defaultOptions = Highcharts.getOptions();
7    for (var prop in defaultOptions) {
8        if (typeof defaultOptions[prop] !== 'function') delete defaultOptions[prop];
9    }
10    // Fall back to the defaults that we captured initially, this resets the theme
11    Highcharts.setOptions(HCDefaults);
12}