angular ng-select ng-option

for array data sources:

• • label for value in array
  • select as label for value in array
  • label group by group for value in array
  • select as label group by group for value in array track by trackexpr

for object data sources:

• • label for (key , value) in object
  • select as label for (key , value) in object
  • label group by group for (key, value) in object
  • select as label group by group for (key, value) in ob