Select2 provides the SingleSelection and MultipleSelection adapters as default implementations of the SelectionAdapter for single- and multi-select controls, respectively. Both SingleSelection and MultipleSelection extend the base BaseSelection adapter.
The selection adapter can be overridden by assigning a custom adapter to the selectionAdapter configuration option.
select2/selection
Placeholder and HidePlaceholderAMD Modules:
select2/selection/placeholder
select2/dropdown/hidePlaceholder
These decorators implement Select2's placeholder features.
AllowClearAMD Modules:
select2/selection/allowClear
This decorator implements clearable selections as exposed through the allowClear option.
EventRelayAMD Modules:
select2/selection/eventRelay
Select2 has an internal event system that is used to notify parts of the component that state has changed, as well as an adapter that allows some of these events to be relayed to the outside word.