> ## Documentation Index
> Fetch the complete documentation index at: https://filecheck.io/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# JavaScript

> The filecheck-js loader — typed, promise-based Element loading plus every shared TypeScript type.

`filecheck-js` replaces the manual `<script>` tag and polling loop with one typed call. It injects the CDN script once (concurrent calls share a single tag), resolves when the Element is ready, and exports the full Element type surface so `elements.create('intake', …)` and every event payload are typed end to end.

```bash theme={null}
npm install filecheck-js
```

## Quickstart

```ts theme={null}
import { loadFilecheck } from 'filecheck-js';

const fc = await loadFilecheck('pk_…');
if (fc) {
  const intake = fc.elements.create('intake', { workflowId: 'wf_…' });

  intake.on('status', ({ canProceed, jobId }) => {
    submitButton.disabled = !canProceed;      // authoritative — never re-derive
    jobIdInput.value = jobId ?? '';           // verify server-side before fulfilling
  });

  intake.mount('#fc-slot');
}
```

Gate your submit button on `canProceed` and send the `jobId` to your server with the form — then [verify it server-side](/docs/server/verify-jobs) before fulfilling.

## `loadFilecheck(publishableKey, options?)`

Returns `Promise<FilecheckInstance | null>`.

| Option          | Type     | Description                                                         |
| --------------- | -------- | ------------------------------------------------------------------- |
| `agentId`       | `string` | Optional sub-tenant scope, passed to the factory.                   |
| `scriptUrl`     | `string` | Override the CDN script URL (staging or self-hosted).               |
| `loadTimeoutMs` | `number` | Reject if the script has not loaded (default 30 000; `0` disables). |

Behavior worth knowing:

* **Idempotent.** Repeated and concurrent calls inject exactly one `<script>` tag and share one promise. A tag you added yourself is reused.
* **SSR-safe.** In a non-browser environment it resolves `null` instead of touching `window`, so you can call it unconditionally in isomorphic code.
* **Recoverable.** A load failure or timeout rejects with a descriptive error; calling `loadFilecheck` again retries the load.

## TypeScript

Every shared type is exported from the package root: `FilecheckInstance`, `IntakeElementOptions`, `ReportElementOptions`, `IntakeUi`, `IntakeStatusPayload`, `IntakeFacts`, `ElementEventMap`, `ProofPayload`, `ConnectorConfig`, and more. `window.Filecheck` is also typed globally, including the static [`Filecheck.mount`](/docs/element/presentation) helper the CDN bundle provides.

From here the API is the standard Element surface — see [Create and mount](/docs/element/create-and-mount) for options and methods, and [Events](/docs/element/events) for every payload.

<Note>
  Using React or Vue? [`filecheck-react`](/docs/integrations/react) and [`filecheck-vue`](/docs/integrations/vue) build on this package and manage the element lifecycle for you.
</Note>