{"ScriptPreparationCode":"const fooKey = Symbol(\u0027fooSymbol\u0027)\r\n\r\nclass Foo {\r\n constructor(value) {\r\n this[fooKey] = true\r\n this.value = value\r\n }\r\n}\r\n\r\nlet arr;\r\n\r\nfunction prepare() {\r\n arr = Array.from({length:1000})\r\n for (let i = 0; i \u003C arr.length; i\u002B\u002B) {\r\n arr[i] = new Foo(i)\r\n }\r\n}\r\n\r\nfunction runInstanceof() {\r\n prepare();\r\n const match = arr.every((foo) =\u003E foo instanceof Foo);\r\n if (!match) throw new Error(\u0027fail!\u0027);\r\n}\r\n\r\nfunction runKeyIn() {\r\n prepare();\r\n const match = arr.every((foo) =\u003E fooKey in foo);\r\n if (!match) throw new Error(\u0027fail!\u0027);\r\n}","TestCases":[{"Name":"instanceof","Code":"runInstanceof()","IsDeferred":false},{"Name":"key in","Code":"runKeyIn()","IsDeferred":false}]}