# PassFn (/docs/api/type-aliases/PassFn)



```ts
type PassFn = (ctx) => void;
```

Defined in: [packages/core/src/passes/registry.ts:6](https://github.com/austenstone/actio/blob/2b01e694a0f76521d8c073f3c6a2e48917d2c9d9/packages/core/src/passes/registry.ts#L6)

The transform a pass performs. Mutates `ctx.data` in place.

## Parameters [#parameters]

### ctx [#ctx]

[`ParseContext`](../interfaces/ParseContext.mdx)

## Returns [#returns]

`void`


## Sitemap

Browse the full documentation: [Markdown sitemap](https://austenstone.github.io/actio/sitemap.md) · [XML sitemap](https://austenstone.github.io/actio/sitemap.xml)