Clear Related Field in Repeater Form

In our case, we have an Order creation form. This form has a repeater field for products and a quantity field.

Forms\Components\Repeater::make('products')
    ->columnSpan(2)
    ->columns()
    ->schema([
        Forms\Components\Select::make('product_id')
            ->options(Product::pluck('name', 'id')->toArray())
            ->disableOptionsWhenSelectedInSiblingRepeaterItems()
        Forms\Components\TextInput::make('quantity'),
    ]),

But this brings us a challenge - what if someone had 1000 stickers selected and then changed their mind about the product and accidentally selected 1000 notebooks? This is something we can prevent by simply resetting the quantity field when the product is changed:

Forms\Components\Repeater::make('products')
    ->columnSpan(2)
    ->columns()
    ->schema([
        Forms\Components\Select::make('product_id')
            ->options(Product::pluck('name', 'id')->toArray())
            ->disableOptionsWhenSelectedInSiblingRepeaterItems()
            ->live()
            ->afterStateUpdated(function (Forms\Set $set) {
                $set('quantity', null);
            }),
        Forms\Components\TextInput::make('quantity'),
    ]),

Just two lines of code and our users have a much better experience.