Collection.delete() fails silently when filter() is used

[epandurski]

In this code:

      const n = await this.tasks
        .where({ userId })
        .filter(task => task.taskType === 'DeleteTransfer' && !uris.has(task.transferUri))
        .delete()

this extends Dexie, and task is a table. n is always zero, even when

      await this.tasks
        .where({ userId })
        .filter(task => task.taskType === 'DeleteTransfer' && !uris.has(task.transferUri))
        .toArray()

returns some objects.

I expect either the deletion to be successful, or to throw error. The documentation does not mention any problems with deleting collections that have filter()s applied.

[dfahlander]

Thanks for the report. Could you create a repro in https://jsitor.com/, https://codesandbox.io/ or jsfiddle? It would help a lot in finding the reason - it may also reveal whether this actually is a bug in dexie or if there is something else that makes it fail.

[epandurski]

Here is the repro: https://jsitor.com/qPJXVESEcb

[dfahlander]

Thanks for a great repro! Indeed, this is a bug that occurs when using filter on a collection on a partial index ("virtual index"). In this case "userId" is indexed together with "createdAt" ([userId+createdAt]). If directly indexing userId by itself the bug does not happen. I will investigate virtual-index-middleware.ts to understand if it fails to emulate the DBCursor correctly.