Select all in optgroup

I've solved this problem. I get the select as an instance and have an event listener for optionSelect and optionDeselect that passes e in as a variable. In each listener I check to see if the select group option has been selected/deselected and then feed the options I would like selected/deselected as an array into the following code (this is the deselect function):

function deselectOptions(options) {
        options.forEach((option) => {
            if (option.selected && !option.disabled) {
                mySelect._selectionModel.deselect(option)
                option.deselect()
            }
        })
        mySelect._updateInputValue()
        mySelect._updateLabelPosition()
        mySelect._updateClearButtonVisibility()
        mySelect._emitValueChangeEvent(e.value)
    }

I found the functions I needed after looking through your Javascript source code.

Hello, MDB doesn't provide such an option.

Hi,

I'm aware that this isn't an option. I'm quite happy to write my own code for this. If I set the selected options manually using setValue() it closes the dropdown. I would like to replicate the way the 'select all' option works, ticking a set of boxes and keeping the dropdown open.

What I would like is a steer on how you implement the 'select all' function so I can replicate it for a limited set of options.