{"ScriptPreparationCode":"function generateID(length = 10) {\r\n const characters = \u0027ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789\u0027;\r\n let result = \u0027\u0027;\r\n const charactersLength = characters.length;\r\n \r\n for (let i = 0; i \u003C length; i\u002B\u002B) {\r\n // Generate a random index based on characters length\r\n const randomIndex = Math.floor(Math.random() * charactersLength);\r\n // Append the character at the random index to the result string\r\n result \u002B= characters[randomIndex];\r\n }\r\n\r\n return result;\r\n}\r\n\r\nconst initialArray = new Array(10000).fill(\u0027a\u0027).map(() =\u003E ({ [generateID()]: \u0027value\u0027 }));\r\n\r\nconst anotherArray = new Array(10000).fill(\u0027b\u0027).map(() =\u003E ({ [generateID()]: \u0027value\u0027 }));","TestCases":[{"Name":"concat (immutable)","Code":"const result = initialArray.concat(anotherArray);","IsDeferred":false},{"Name":"push (mutability) and spread array","Code":"initialArray.push(...anotherArray);","IsDeferred":false},{"Name":"push (mutability) and iteration","Code":"anotherArray.forEach(item =\u003E initialArray.push(item));","IsDeferred":false}]}