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

```ts
function todo<T>(): T;
```

Defined in: [packages/common/src/Function.ts:312](https://github.com/evoluhq/evolu/blob/ca15b4661c40fedb9f47434497086039cbdea38e/packages/common/src/Function.ts#L312)

Development placeholder that always throws.

Use to sketch function bodies before implementing them. TypeScript infers the
return type from context, so surrounding code still type-checks. Use an
explicit generic when there is no return type annotation.

### Example

```ts

interface Config {
  readonly theme: string;
}

const getCount = (): number => todo();
const getConfig = () => todo<Config>();

expectTypeOf<
  [ReturnType<typeof getCount>, ReturnType<typeof getConfig>]
>().toEqualTypeOf<[number, Config]>();
expect(getCount).toThrow("not yet implemented");
```