simplify multiple filters in flutter - flutter

Question

here is my code
value = data.where((i) => (i.type == 1 || i.type == 3)).toList();
if (data.length == 0) {
_final = null;
} else {
dataDefault = value .where((i) => i.isdefault == 1).toList();
}
if (dataDefault.length == 0) {
data[0].isdefault = 1;
}
finalvalue = dataDefault.where((i) => i.isdefault == 1).toList();
Here is my json
[
{
"id": 129,
"type": 3,
"is_default": 1
},
{
"id": 130,
"type": 1,
"is_default": 0
},
{
"id": 131,
"type": 5,
"is_default": 1
}
]
What i need is ,i need to check if the array is in type 1 or 3 if no array available i need to set first array and change as default and then i want to filter the whole array and check default field
It is working fine but i need to simplify the code and also needs to know the approach is correct

Answer 1

From your description, I get the original request is:
if(array not contains type1 or type3){
set array[0] to default
}
result <- get all 'is default' from array
Simplified version:
var result; // null as default
if (data != null) {
if(data.where((i) => (i.type == 1 || i.type == 3)).isEmpty) {
data[0].isdefault = 1;
}
result = data.where((i) => i.isdefault == 1).toList();
}
Or use null safety check ? and ??
if(data?.where((i) => (i.type == 1 || i.type == 3))?.isEmpty ?? false){
data[0].isdefault = 1;
}
final result = data?.where((i) => i.isdefault == 1)?.toList();