[feat] convert a single string variable to a string, without []

Author: fangq

savejson.m

@@ -289,7 +289,7 @@
 %% -------------------------------------------------------------------------
 function txt = obj2json(name, item, level, varargin)
 
-if (iscell(item) || isa(item, 'string'))
+if (iscell(item) || (isa(item, 'string') && numel(item) > 1))
     txt = cell2json(name, item, level, varargin{:});
 elseif (isa(item, 'jdict'))
     txt = obj2json(name, item, level, varargin{:});

test/run_jsonlab_test.m

@@ -53,7 +53,7 @@ function run_jsonlab_test(tests)
     test_jsonlab('empty string', @savejson, '', '""', 'compact', 1);
     test_jsonlab('string escape', @savejson, sprintf('jdata\n\b\ashall\tprevail\t"\"\\'), '"jdata\n\b\ashall\tprevail\t\"\"\\"');
     if (exist('string'))
-        test_jsonlab('string type', @savejson, string(sprintf('jdata\n\b\ashall\tprevail')), '["jdata\n\b\ashall\tprevail"]', 'compact', 1);
+        test_jsonlab('string type', @savejson, string(sprintf('jdata\n\b\ashall\tprevail')), '"jdata\n\b\ashall\tprevail"', 'compact', 1);
         test_jsonlab('string array', @savejson, [string('jdata'), string('shall'), string('prevail')], '["jdata","shall","prevail"]', 'compact', 1);
     end
     test_jsonlab('empty name', @savejson, loadjson('{"":""}'), '{"":""}', 'compact', 1);