[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › [Option](https://evolu.dev/docs/api-reference/common/Option) › isSome

```ts
function isSome<T>(option: Option<T>): option is Some<T>;
```

Defined in: [packages/common/src/Option.ts:60](https://github.com/evoluhq/evolu/blob/e7144e2bbe9069362b62dec1b64a8aa922b8f1b0/packages/common/src/Option.ts#L60)

Type guard for [Some](https://evolu.dev/docs/api-reference/common/Option/interfaces/Some).