The expression [...new Set(recordIdArray)] in JavaScript provides a simple and efficient way to remove duplicates from an array. The Set object inherently stores only unique values, so when you passrecordIdArray to new Set(), all duplicate elements are automatically filtered out. The spread operator ... then converts the set back into a regular array, preserving the unique elements in an easily accessible format. This method is concise and much cleaner compared to using loops or conditional logic to achieve the same result. It is particularly useful in scenarios involving large datasets, ensuring data integrity without unnecessary complexity. Moreover, using this approach can improve performance when handling extensive records or lists in applications. Its simplicity and efficiency make it a preferred choice for modern developers working with arrays.