GEE: Adding two properties into a new property

Question

I want to add the values of two properties A and B (both of type string) into a new property A_B to every feature inside the featureCollection.

I tried ee.Feature.get() and ee.Feature.getString() to read the values of properties into two new variables inside my map() function. But they return not "string" values but "tree" type structures.

var add_mix_AB = function(f){
  var A = f.getString(['A']);
  var B = f.getString(['B']);
  return f.set('A_B', A+B);
 };

Answer 1

OK I figured out the issue was :

1. In the way I "got" the strings. (the name of property should not have been given inside a list.)

2. "added" them together. (I had to use the .cat() function to add two strings)

The corrected snipet will be :

var add_mix_AB = function(f){
  var A = f.getString('A');
  var B = f.getString('B');
  return f.set('A_B', A.cat(B));
};