type TransactionWithMutations<T, TOperation> = Omit<Transaction<T>, "mutations"> & object;

type TransactionWithMutations<T, TOperation> = Omit<Transaction<T>, "mutations"> & object;

Defined in: packages/db/src/types.ts:139

Utility type for a Transaction with at least one mutation This is used internally by the Transaction.commit method

mutations: NonEmptyArray<PendingMutation<T, TOperation>>;

mutations: NonEmptyArray<PendingMutation<T, TOperation>>;

We must omit the mutations property from Transaction<T> before intersecting because TypeScript intersects property types when the same property appears on both sides of an intersection.

Without Omit:

• Transaction<T> has mutations: Array<PendingMutation<T>>
• The intersection would create: Array<PendingMutation<T>> & NonEmptyArray<PendingMutation<T, TOperation>>
• When mapping over this array, TypeScript widens TOperation from the specific literal (e.g., "delete") to the union OperationType ("insert" | "update" | "delete")
• This causes PendingMutation<T, OperationType> to evaluate the conditional type original: TOperation extends 'insert' ? {} : T as {} | T instead of just T

With Omit:

• We remove mutations from Transaction<T> first
• Then add back mutations: NonEmptyArray<PendingMutation<T, TOperation>>
• TypeScript can properly narrow TOperation to the specific literal type
• This ensures mutation.original is correctly typed as T (not {} | T) when mapping

T extends object = Record<string, unknown>

TOperation extends OperationType = OperationType