# from-latest-event-incomplete

**`fromLatestEvent`** leaves out its subject, its type, or `ifEventIsMissing`.

- **Routes:** `read-events` and `observe-events`
- **Description:**
    - without `subject`: `fromLatestEvent is incomplete: expected a subject`
    - without `type`: `fromLatestEvent is incomplete: expected a type`
    - without `ifEventIsMissing`: `fromLatestEvent is incomplete: expected ifEventIsMissing`
- **Details:** **`field`**, the field that is left out: `subject`, `type`, or `ifEventIsMissing`.

## Why It Happens

The option **`fromLatestEvent`** starts a read or an observation at the **[latest event of a type](/learn/tutorials/first-steps-with-eventsourcingdb/reading-events#reading-from-the-last-event-of-a-given-type)** in a subject, and it needs **all three of its fields**: the `subject` and the `type` of that event, and `ifEventIsMissing`, which says what to do if there is no such event. None of them has a default, and an empty string counts as left out. A typical cause is a `fromLatestEvent` that names the subject and the type, but leaves out `ifEventIsMissing`.

The fields are checked in the order `subject`, `type`, `ifEventIsMissing`, and the error names the first that is missing. Their values are checked only afterwards: an unknown value of `ifEventIsMissing` is reported as **[`if-event-is-missing-unknown`](/docs/eventsourcingdb/errors/if-event-is-missing-unknown)**, a subject that is not valid as **[`subject-malformed`](/docs/eventsourcingdb/errors/subject-malformed)**, and a type that is not valid as **[`event-type-malformed`](/docs/eventsourcingdb/errors/event-type-malformed)**.

## How to Fix It

Send `fromLatestEvent` with all three fields. For `ifEventIsMissing`, send `read-everything` or `read-nothing` when reading, and `read-everything` or `wait-for-event` when observing. Sending the same request again fails the same way.

## Example

To read the events of `/books/42` from its latest `io.eventsourcingdb.library.book-borrowed` event, without `ifEventIsMissing`, EventSourcingDB answers with this error, as a line of the stream, and then ends the stream with its `end` item:

```json
{
  "type": "error",
  "data": {
    "code": "https://docs.eventsourcingdb.io/errors/from-latest-event-incomplete",
    "description": "fromLatestEvent is incomplete: expected ifEventIsMissing",
    "details": {
      "field": "ifEventIsMissing"
    }
  }
}
```