Duplicates

Set duplicateKey on the component (or hosted config) to a field key (for example email). After coercion, non-empty values are compared case-insensitively. The first row wins. Later rows get an error on that field: Duplicate of row N (1-based).

Email cell on row 3 marked Duplicate of row 1.

Set unique: true on one or more fields when several columns must be unique independently (for example both email and sku). Empty optional values do not participate in uniqueness.

Both checks are in-file only. They do not query your database for existing records. Do that in your API after onComplete.