What is happening is that it doesn't work if destination array is already predefined.
If I set destination array as predefined and then try to add more items I'm getting the error:
custom-listbox.component.html:22 ERROR TypeError: Cannot add property 2, object is not extensible
at Array.push (<anonymous>)
at _loop_1 (angular-dual-listbox.js:416)
at CustomListboxComponent.push../node_modules/angular-dual-listbox/fesm5/angular-dual-listbox.js.DualListComponent.trueUp (angular-dual-listbox.js:424)
at CustomListboxComponent.push../node_modules/angular-dual-listbox/fesm5/angular-dual-listbox.js.DualListComponent.moveItem (angular-dual-listbox.js:565)
at Object.handleEvent (custom-listbox.component.html:22)
at handleEvent (core.js:29239)
at callWithDebugContext (core.js:30309)
at Object.debugHandleEvent [as handleEvent] (core.js:30036)
at dispatchEvent (core.js:19859)
at core.js:28448
What is happening is that it doesn't work if destination array is already predefined.
If I set destination array as predefined and then try to add more items I'm getting the error: