How to prevent all checkboxes from being cleared?

Question

JavaScript

Good afternoon.
There are several checkboxes - they are checked.
It is necessary to prevent the removal of all checkboxes - at least one must be selected. Those. the last selected one must not be removed.
How to do this in angularjs or just javascript?
Thanks

Answer 1

On Angular, create an object for binding checkboxes. And a separate function under ng-click, inside on click you check the number of true in the object and, if there is more than one true, then you change the value.