Dart encodeUriComponent Map.keys() - dictionary

Question

There is an example that I have seen in a number of places for encoding a Map as follows:
#import('dart:uri');
String encodeMap(Map data) {
return Strings.join(data.getKeys().map((k) {
return "${encodeUriComponent(k)}=${encodeUriComponent(data[k])}";
}), "&");
}
I'm running what appears to be the latest Dart editor (version 0.2.9_r 16323)
in the above example, for Dart M2, I believe that data.getKeys() has been changed to data.keys() which I have altered.
However, I get an error when running it in the Editor:
Exception: NoSuchMethodError : method not found: 'call'"
I have 2 questions:
I'm wondering if this above code should still work in M2 with the change indicated (Map.keys())?
I'm wondering if this above code does something different to: JSON.stringify(data);
Any other pointers are welcome.
TIA.

Answer 1

Two changes to do :
import syntax has changed.
getKeys() method became a getter called keys.
A working version :
import 'dart:uri';
String encodeMap(Map data) {
return Strings.join(data.keys.map((k) {
return "${encodeUriComponent(k)}=${encodeUriComponent(data[k])}";
}), "&");
}
The String generated by this encodeMap is quite different from the one generated by JSON.stringify as you can see in the bellow snippet :
main() {
final map = {"a":"b", "c":"d"};
assert(encodeMap(map) == "a=b&c=d");
assert(JSON.stringify(map) == '{"a":"b","c":"d"}');
}