Converter<String, Number> converter = Converter.<String, Number>from(forward, backward);

    assertNull(converter.convert(null));
    assertNull(converter.reverse().convert(null));

    assertEquals((Integer) 5, converter.convert("5"));
    assertEquals("5", converter.reverse().convert(5));
  }

  // Null-passthrough violates our nullness annotations, so we don't support it under J2KT.
  @J2ktIncompatible

    assertEquals(TestEnum.CHEETO, converter.convert("CHEETO"));
    assertEquals(TestEnum.HONDA, converter.convert("HONDA"));
    assertEquals(TestEnum.POODLE, converter.convert("POODLE"));
    assertNull(converter.convert(null));
    assertNull(converter.reverse().convert(null));
  }

  @GwtIncompatible // stringConverter
  public void testStringConverter_convertError() {

                            }))
                    .installationToolchainsSource(convert(request.getGlobalToolchainsSource()))
                    .userToolchainsSource(convert(request.getUserToolchainsSource()))
                    .build());

            return new DefaultToolchainsBuildingResult(
                    new PersistedToolchains(result.getEffectiveToolchains()), convert(result.getProblems()));
        } catch (ToolchainsBuilderException e) {

    assertThat(converter.convert("1.0")).isEqualTo((Double) 1.0);
    assertThat(converter.convert("0.0")).isEqualTo((Double) 0.0);
    assertThat(converter.convert("-1.0")).isEqualTo((Double) (-1.0));
    assertThat(converter.convert("1")).isEqualTo((Double) 1.0);
    assertThat(converter.convert("0")).isEqualTo((Double) 0.0);
    assertThat(converter.convert("-1")).isEqualTo((Double) (-1.0));

# 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.

    if (MINUTES.convert(nanos, NANOSECONDS) > 0) {
      return MINUTES;
    }
    if (SECONDS.convert(nanos, NANOSECONDS) > 0) {
      return SECONDS;
    }
    if (MILLISECONDS.convert(nanos, NANOSECONDS) > 0) {
      return MILLISECONDS;
    }
    if (MICROSECONDS.convert(nanos, NANOSECONDS) > 0) {
      return MICROSECONDS;
    }
    return NANOSECONDS;
  }

  private static String abbreviate(TimeUnit unit) {

			return false, store.ErrNotConnected
		}
	}

	if connErr != nil {
		if connErr.Error() == nats.ErrNoServers.Error() {
			return false, store.ErrNotConnected
		}
		return false, connErr
	}

	if target.natsConn != nil && target.args.JetStream.Enable {
		target.jstream, connErr = target.natsConn.JetStream()
		if connErr != nil {
			if connErr.Error() == nats.ErrNoServers.Error() {

            result.addDependency(convert(dependency, stereotypes));
        }

        DependencyManagement mgmt = model.getDependencyManagement();
        if (mgmt != null) {
            for (org.apache.maven.model.Dependency dependency : mgmt.getDependencies()) {
                result.addManagedDependency(convert(dependency, stereotypes));
            }
        }

    assertThat(converter.convert("1")).isEqualTo((Integer) 1);
    assertThat(converter.convert("0")).isEqualTo((Integer) 0);
    assertThat(converter.convert("-1")).isEqualTo((Integer) (-1));
    assertThat(converter.convert("0xff")).isEqualTo((Integer) 255);
    assertThat(converter.convert("0xFF")).isEqualTo((Integer) 255);
    assertThat(converter.convert("-0xFF")).isEqualTo((Integer) (-255));

    assertThat(converter.convert("1")).isEqualTo((Long) 1L);
    assertThat(converter.convert("0")).isEqualTo((Long) 0L);
    assertThat(converter.convert("-1")).isEqualTo((Long) (-1L));
    assertThat(converter.convert("0xff")).isEqualTo((Long) 255L);
    assertThat(converter.convert("0xFF")).isEqualTo((Long) 255L);
    assertThat(converter.convert("-0xFF")).isEqualTo((Long) (-255L));