[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › [local‑first/Timestamp](https://evolu.dev/docs/api-reference/common/local-first/Timestamp) › timestampToDateIso

```ts
function timestampToDateIso(timestamp: Timestamp): string & Brand<"DateIso">;
```

Defined in: [packages/common/src/local-first/Timestamp.ts:347](https://github.com/evoluhq/evolu/blob/e7144e2bbe9069362b62dec1b64a8aa922b8f1b0/packages/common/src/local-first/Timestamp.ts#L347)

Convert a [Timestamp](https://evolu.dev/docs/api-reference/common/local-first/Timestamp/variables/Timestamp) to an ISO 8601 [DateIso](https://evolu.dev/docs/api-reference/common/Type/variables/DateIso) string.

The conversion uses the timestamp's `millis` (a [Millis](https://evolu.dev/docs/api-reference/common/Time/variables/Millis) value) and
`Date.prototype.toISOString()` to produce a `DateIso`.