Handle struct array in m2json

Author: robertoffmoura

plotly/plotly_aux/Test_m2json.m

@@ -101,6 +101,13 @@ function testStruct(tc)
             tc.verifyEqual(m2json(values), expected);
         end
 
+        function testStructArray(tc)
+            values = struct("a", 1, "b", "text");
+            values = [values values];
+            expected = "[{""a"" : 1, ""b"" : ""text""}, {""a"" : 1, ""b"" : ""text""}]";
+            tc.verifyEqual(m2json(values), expected);
+        end
+
         function testDatetime(tc)
             value = datetime("2023-05-01 12:30:45");
             expected = """2023-05-01 12:30:45""";

plotly/plotly_aux/struct2json.m

@@ -1,4 +1,13 @@
 function str = struct2json(s)
+    if isscalar(s)
+        str = oneStruct2json(s);
+    else
+        str = arrayfun(@oneStruct2json,s);
+        str = sprintf("[%s]",strjoin(str,", "));
+    end
+end
+
+function str = oneStruct2json(s)
     f = fieldnames(s);
     strList = cellfun(@(x) sprintf('"%s" : %s', x, m2json(s.(x))), f, 'un', 0);
     str = sprintf("{%s}", strjoin(strList, ", "));