{"ScriptPreparationCode":null,"TestCases":[{"Name":"string concatenate","Code":"let obj = {}\r\nfor(let i = 0; i \u003C 1000; i\u002B\u002B) {\r\n obj[\u0022a\u0022\u002Bi] = 0\r\n}\r\nlet columns = \u0022\u0022\r\nfor(let y in obj) {\r\n columns \u002B= (y \u002B \u0022, \u0022)\r\n}\r\ncolumns = \u0022(\u0022 \u002B columns.slice(0, -2) \u002B \u0022)\u0022","IsDeferred":false},{"Name":"array join","Code":"let obj = {}\r\nfor(let i = 0; i \u003C 1000; i\u002B\u002B) {\r\n obj[\u0022a\u0022\u002Bi] = 0\r\n}\r\nlet columns = Object.keys(obj).join(\u0022, \u0022)","IsDeferred":false}]}