dart - Combine/merge multiple maps into 1 map

Question

How can I combine/merge 2 or more maps in dart into 1 map? for example I have something like:

 var firstMap = {"1":"2"};
 var secondMap = {"1":"2"};
 var thirdMap = {"1":"2"};

I want:

 var finalMap = {"1":"2", "1":"2", "1":"2"};

Answer 1

you can use addAll method of Map object

var firstMap = {"1":"2"};
var secondMap = {"2":"3"};

var thirdMap = {};

thirdMap.addAll(firstMap);
thirdMap.addAll(secondMap);

print(thirdMap);

Or

var thirdMap = {}..addAll(firstMap)..addAll(secondMap);

Update

Since dart sdk 2.3 You can use spread operator ...

final firstMap = {"1":"2"};
final secondMap = {"2":"3"};

final thirdMap = {
   ...firstMap,
   ...secondMap,
};