var string = "passw)odas4gsdfsdf";

{"ScriptPreparationCode":"var string = \u0022aaaaabbbbbccccddd\u0022;","TestCases":[{"Name":"RegEx","Code":"var s = string.match(/([a-zA-Z])\\1*/g)||[];\r\nreturn s.map(function(itm){\r\n return [itm.charAt(0), itm.length];\r\n});","IsDeferred":false},{"Name":"For Loop","Code":"var result = [[string[0], 1]]\r\nfor(let i = 1; i \u003C string.length; i\u002B\u002B) {\r\n const char = string[i]\r\n const lastChar = result.at(-1)\r\n \r\n if(char === lastChar[0]){\r\n\tlastChar[1] = lastChar[1] \u002B 1\r\n } else {\r\n\tresult.push([char, 1])\r\n }\r\n}","IsDeferred":false}]}