main.dart

var arr = [];
var arr1;

var crit = {"prsn": "", "age": 20, "color": ""};

void main() {
  for (int i = 0; i < 3; i++) {
    arr.add({"prsn": "name${i + 1}", "age": 25 + i, "color": "green"});
    //arr[i]=i+1;
  }
  arr[1]['color'] = "yellow";
  arr[2]['color'] = "red";

  arr.add({"prsn": "name1", "age": 20, "color": "blue"});
  arr.add({"prsn": "name5", "age": 25, "color": "green"});

  print("actual array\n$arr");

  arr1 = arr;

  if (crit["prsn"] != null && crit["prsn"].toString().length > 0)
    arr1 = arr1.where((ele) => ele["prsn"] == crit["prsn"]);
  if (crit["age"] != null)
    arr1 = arr1.where((ele) => ele["age"] == crit["age"]);
  if (crit["color"] != null && crit["color"].toString().length > 0)
    arr1 = arr1.where((ele) => ele["color"] == crit["color"]);

  print("\nfiltered array\n$arr1");
}