How can I swap the order of two selected tasks

Gantt
#1

Hi~,
I need to specify two tasks to exchange positions
Here is an example. On the surface, it seems that I need it, but in essence, I find that I don’t realize the position exchange of two specified tasks
well

#2

Hello,
If you want to swap the position of two tasks, and you know its IDs, then you can use moveTask method to change the positions of the required tasks:
https://docs.dhtmlx.com/gantt/api__gantt_movetask.html ;
You need to get the index and the parent of the task by getTaskIndex and getParent methods:
https://docs.dhtmlx.com/gantt/api__gantt_gettaskindex.html;
https://docs.dhtmlx.com/gantt/api__gantt_getparent.html ;
So, to swap certain tasks might look like:

function swap() {
        let temp_ind = gantt.getTaskIndex(1)
        let temp_par = gantt.getParent(1)
        gantt.moveTask(1, gantt.getTaskIndex(4), gantt.getParent(4));
        gantt.moveTask(4, temp_ind, temp_par);
}

where temp_ind, temp_par temporary variables that hold the value of the initial task.
Please check the example:
https://snippet.dhtmlx.com/xuwfgkfm ;
Also, If you want to swap two selected tasks, one of the options is to use multiselect extension to select certain tasks and using moveTask method:
https://docs.dhtmlx.com/gantt/desktop__multiselection.html ;
You can use eachSelectedTask method to get all selected tasks:
https://docs.dhtmlx.com/gantt/api__gantt_eachselectedtask.html ;
Please check the example of how it might be implemented (select two tasks by ctrl + click and click at the button):
https://snippet.dhtmlx.com/u1xui7vc