return result
  }
  synchronized(BROWSER_COMPATIBLE_DATE_FORMAT_STRINGS) {
    for (i in 0 until BROWSER_COMPATIBLE_DATE_FORMAT_STRINGS.size) {
      var format: DateFormat? = BROWSER_COMPATIBLE_DATE_FORMATS[i]
      if (format == null) {
        format =
          SimpleDateFormat(BROWSER_COMPATIBLE_DATE_FORMAT_STRINGS[i], Locale.US).apply {

# JSON Compatible Encoder

There are some cases where you might need to convert a data type (like a Pydantic model) to something compatible with JSON (like a `dict`, `list`, etc).

For example, if you need to store it in a database.

For that, **FastAPI** provides a `jsonable_encoder()` function.

## Using the `jsonable_encoder`

Let's imagine that you have a database `fake_db` that only receives JSON compatible data.

            assertHasAccepted(
                "Method com.example.Task.getSourceCompatibility(): Is not binary compatible. Reason for accepting this: Upgraded property" to listOf("Method return type has changed", "Method is now abstract"),
                "Method com.example.Task.setSourceCompatibility(java.lang.String): Is not binary compatible. Reason for accepting this: Upgraded property" to listOf("Method has been removed")
            )
        }
    }

dthedocs.io/en/stable/" class="external-link" target="_blank">AnyIO</a>, which makes them compatible with both Python's standard library <a href="https://docs.python.org/3/library/asyncio-task.html" class="external-link" target="_blank">asyncio</a> and <a href="https://trio.readthedocs.io/en/stable/" class="external-link" target="_blank">Trio</a>.

Nevertheless, Uvicorn is currently only compatible with asyncio, and it normally uses <a href="https://github.com/MagicStack/uvloop" class="external-link"...

        Any next read or write will be done from that position.

        To be awaitable, compatible with async, this is run in threadpool.
        """
        return await super().seek(offset)

    async def close(self) -> None:
        """
        Close the file.

        To be awaitable, compatible with async, this is run in threadpool.
        """
        return await super().close()

    timestamp: datetime
    description: Union[str, None] = None


app = FastAPI()


@app.put("/items/{id}")
def update_item(id: str, item: Item):
    json_compatible_item_data = jsonable_encoder(item)

compatibles avec <a href="https://docs.python.org/3/library/asyncio-task.html" class="external-link" target="_blank">asyncio</a>, de la bibliothèque standard Python et
<a href="https://trio.readthedocs.io/en/stable/" class="external-link" target="_blank">Trio</a>.

Néanmoins, Uvicorn n'est actuellement compatible qu'avec asyncio, et il utilise normalement <a href="https://github.

    title: str
    timestamp: datetime
    description: str | None = None


app = FastAPI()


@app.put("/items/{id}")
def update_item(id: str, item: Item):
    json_compatible_item_data = jsonable_encoder(item)

 * serialization tests require more setup. This no-op behavior allows test authors to intersperse
 * {@code SerializableTester} calls with other, GWT-compatible tests.
 *
 * @author Mike Bostock
 * @since 10.0
 */
@GwtCompatible // but no-op!
@ElementTypesAreNonnullByDefault
public final class SerializableTester {
  private SerializableTester() {}

  /**

Par défaut, **FastAPI** convertirait automatiquement cette valeur de retour en JSON en utilisant le `jsonable_encoder` expliqué dans [JSON Compatible Encoder](../tutorial/encoder.md){.internal-link target=_blank}.

Ensuite, en arrière-plan, il mettra ces données JSON-compatible (par exemple un `dict`) à l'intérieur d'un `JSONResponse` qui sera utilisé pour envoyer la réponse au client.