{"ScriptPreparationCode":"var x = {\r\n foo: []\r\n};\r\nvar keys = Array.from({\r\n length: 5000\r\n}).map((x, i) =\u003E i \u003C 2500 ? i : i - 2500);","TestCases":[{"Name":"hasOwnProperty membership check","Code":"for (const key of keys) {\r\n if (!Object.prototype.hasOwnProperty.call(x, key)) {\r\n x[key] = [];\r\n }\r\n}","IsDeferred":false},{"Name":"self-assignment","Code":"for (const key of keys) {\r\n x[key] = x[key] ?? [];\r\n}","IsDeferred":false},{"Name":"in membership check","Code":"for (const key of keys) {\r\n if (!(key in x)) {\r\n x[key] = [];\r\n }\r\n}","IsDeferred":false}]}