# API

> Everything fondu, fondu/client and fondu/vite export.

## `fondu`

The server's API, for `app/server.ts`, routes and middleware.

### `createApp()`

`createApp(options?)` returns the Hono app made of `app/routes/`.

| Option          |                                                                                        |
| --------------- | -------------------------------------------------------------------------------------- |
| `document`      | the HTML around pages: `({ head, body, c }) => string`: [The document](https://fondu.dev/docs/document.md) |
| `errorPage`     | the page for errors, `'error'` by default; `false`: plain text                         |
| `trailingSlash` | `'trim'` (default: `/users/` redirects to `/users`) or `'append'`                      |
| `csrf`          | `hono/csrf`'s options, or `false`                                                      |
| `secureHeaders` | `hono/secure-headers`' options, or `false`                                             |

The Content Security Policy by default: `default-src 'self'`; scripts of the site or with the request's nonce (the
document's scripts have it); inline styles (React's style attributes); `data:` images and fonts;
`object-src 'none'`; `base-uri 'self'`. A directive of yours replaces that one only:

```ts
createApp({
  secureHeaders: { contentSecurityPolicy: { fontSrc: ["'self'", 'https://fonts.gstatic.com'] } },
})
```

`contentSecurityPolicy: false`: no policy.

### Handlers

| Export                                                 |                                                                         |
| ------------------------------------------------------ | ----------------------------------------------------------------------- |
| `defineHandler(...middleware, handler)`                | a route's handler: Hono's `createHandlers`                              |
| `defineHandler.withValidator({ body, query, params })` | the same, with input checked by Standard Schemas: `(c, input) => …`     |
| `defineMiddleware(fn)`                                 | a middleware: Hono's `createMiddleware`                                 |
| `withoutSsr()`                                         | a middleware: these pages render in the browser only                    |
| `ValidationError`                                      | `throw new ValidationError({ field: 'message' })`: back with the errors |

### Responses

| Export                              |                                                                                        |
| ----------------------------------- | -------------------------------------------------------------------------------------- |
| `render(c, page, props?, options?)` | a page; options: `status`, `encryptHistory`, `clearHistory`, `preserveFragment`        |
| `share(c, props)`                   | props every page of this request gets                                                  |
| `flash(c, data)`                    | data for the next page (`usePage().flash`)                                             |
| `back(c, fallback?)`                | a redirect to the page the request came from                                           |
| `location(c, url)`                  | a full page load of `url`                                                              |
| `clearHistory(c)`                   | clears the encrypted history on the next page                                          |
| `isInertia(c)`, `wantsPage(c)`      | whether the request is an Inertia visit; whether it wants a page (or is an API client) |

### Props

| Export                             |                                                       |
| ---------------------------------- | ----------------------------------------------------- |
| `optional(fn)`                     | only when a partial reload asks for it                |
| `always(value)`                    | on every partial reload                               |
| `defer(fn, { group?, rescue? })`   | after the page renders                                |
| `merge(value)`, `prepend(value)`   | appended to, or prepended to, the list the page holds |
| `deepMerge(value, { matchOn? })`   | merged into the object the page holds                 |
| `once(fn, { key?, ttl?, fresh? })` | when the browser doesn't hold it already              |
| `scroll(fn, { pageName? })`        | a page of a list, for `<InfiniteScroll>`              |

[Pages and props](https://fondu.dev/docs/pages.md#kinds-of-props) shows them in use.

### Route exports

| Export                                             |                                                                                   |
| -------------------------------------------------- | --------------------------------------------------------------------------------- |
| `loader`                                           | GET                                                                               |
| `action`                                           | POST                                                                              |
| `actions = { name }`                               | POST `?name`                                                                      |
| `GET`, `POST`, `PUT`, `PATCH`, `DELETE`, `OPTIONS` | HTTP handlers                                                                     |
| `prerender`                                        | `true`, `false` or a function listing params: a [static page](https://fondu.dev/docs/static-pages.md) |
| `default` (in `_middleware.ts`)                    | the directory's middleware                                                        |

## `fondu/client`

For the browser.

| Export                |                                                                |
| --------------------- | -------------------------------------------------------------- |
| `href(path, params?)` | a URL of `app/routes/`, typed: `href('/users/:id', { id: 7 })` |

## `fondu/vite`

The Vite plugin: `fondu(options)`.

| Option      |                                                                                   |
| ----------- | --------------------------------------------------------------------------------- |
| `target`    | `'node'`, `'bun'` or `'cloudflare'`                                               |
| `port`      | the production port on Node and Bun, 3000 by default (`PORT` overrides it)        |
| `ssr`       | `false`: pages render in the browser only                                         |
| `prerender` | `true`: write the chosen pages as [static files](https://fondu.dev/docs/static-pages.md) (Cloudflare) |
| `react`     | options for `@vitejs/plugin-react`                                                |