{"ScriptPreparationCode":"var arr = [];\r\nfor (let i = 0; i \u003C 1000; i\u002B\u002B) arr[i] = i;\r\n\r\nfunction randomKey() {\r\n return Math.floor(Math.random() * 2000);\r\n}","TestCases":[{"Name":"Undefined ","Code":"let r = arr[randomKey()] !== undefined;","IsDeferred":false},{"Name":"In","Code":"let r = randomKey() in arr;","IsDeferred":false}]}