fix(transactions): always resolve isPersisted.promise (#376)

Author: tomkuehl

packages/db/src/transactions.ts

@@ -355,6 +355,7 @@ class Transaction<T extends object = Record<string, unknown>> {
 
     if (this.mutations.length === 0) {
       this.setState(`completed`)
+      this.isPersisted.resolve(this)
 
       return this
     }

packages/db/tests/transactions.test.ts

@@ -25,6 +25,7 @@ describe(`Transactions`, () => {
 
     transaction.commit()
     expect(transaction.state).toBe(`completed`)
+    expect(transaction.isPersisted.promise).resolves.toBeDefined()
   })
   it(`thows an error if you don't pass in mutationFn`, () => {
     // @ts-expect-error missing argument on purpose