label for value in array

選擇的是:{{ role1.name + '(' + role1.age + ')' }}

select as label for value in array

選擇的是:{{ role2 }}

label group by group for value in array

選擇的是:{{ role3.name + '(' + role3.age + ')' }}

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

選擇的是:{{ role4.name + '(' + role4.age + ')' }}