How to select multiple objects in svg?

Question

JavaScript

Greetings.
There is a need to highlight objects on svg, all objects are on the same level. Please help me find a solution.
Select means to hang an event around the perimeter of the mouse passage. How to select folders on a PC.

There is an example. https://editor.method.ac/ draw some objects on it, click the mouse button in the left corner and select the group.

This is the solution you need. But not the editor, but only the possibility of selection.

The editor itself is on github, but the code is very large.