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

```ts
type FsOpenFlag =
  | "a"
  | "ax"
  | "a+"
  | "ax+"
  | "as"
  | "as+"
  | "r"
  | "r+"
  | "rs+"
  | "w"
  | "wx"
  | "w+"
  | "wx+";
```

Defined in: [packages/common/src/Fs.ts:210](https://github.com/evoluhq/evolu/blob/ecbac001e0c18bbc45b44715f49ecc3a768c5ec9/packages/common/src/Fs.ts#L210)

Supported file opening modes for [Fs.writeFile](https://evolu.dev/docs/api-reference/common/Fs/interfaces/Fs#writefile).