We have built a dynamic Highcharts Gantt Project Management and added a feature to collapse/expand all the groups/tasks. It works but only for few groups, when there is a huge number of groups, it takes many times to expand/collapse. A sample is visible here : https://jsfiddle.net/vegaelce/maxrbgLe In this example, only the first 5 groups are collapsed/expanded when you click on the "+" / "-" buttons. But if you comment the line (collapse/expand only the first 5 groups)
var tab_idx=[0,9,19,23,27];
and uncomment the line (collapse/expand all the 34 groups)
//var tab_idx=[0,9,19,23,27,31,35,39,43,47,51,55,59,68,72,76,82,86,90,94,98,102,106,112,116,120,124,128,132,136,140,144,148,152,];
you'll see that the page is responding after a long time. Is there a better way to achieve that and make faster the collapse/expand for a large group ?
Unfortunately, with such a large amount of data, due to the limitations of target users' browsers and devices, the chart will take longer to load. I suggest limiting the data displayed in one chart, not only for reasons of optimization but also for readability.