npm package: @formsort/web-embed-api
Description: Embed Formsort flows within other webpages
Author: Formsort Engineering
Latest version: 2.10.0

# @formsort/web-embed-api

Embed [Formsort](https://formsort.com) flows within other webpages, with communication between the embed and the parent page.

If you're using React, see [@formsort/react-embed](../react-embed) which is a handy wrapper around this.

## Usage

First, install

```shell
yarn add @formsort/web-embed-api
```

```shell
npm install @formsort/web-embed-api --save
```

Then, initialize the embed and load a flow.

## Documentation

### FormsortWebEmbed(rootEl: HTMLElement, config?: IFormsortWebEmbedConfig)

Initializes a Formsort iframe as a child of the `rootEl` provided.

```ts
const embed = FormsortWebEmbed(document.body);
```

The optional `config` object has the following interface:

```ts
interface IFormsortWebEmbedConfig {
  useHistoryAPI?: boolean; // Default: false
  /**
   * iframe title attribute for accessibility
   */
  iframeTitle?: string;
  /**
   * iframe allow attribute for permissions
   * e.g. "camera;"
   */
  iframeAllow?: string;
  autoHeight?: boolean; // Default: false
  style?: {
    width?: CSSStyleDeclaration['width'];
    height?: CSSStyleDeclaration['height'];
  };
  authentication?: {
    idToken?: string; // ID Token for authenticated flows
  };
  origin?: string; // optional -- use if you want to load your flow in a custom damain. e.g. https://acme-flow.com
}
```

#### `config` properties

- `useHistoryAPI`: When redirecting, should we use the HTML5 History API (namely, `window.pushState`), or just change the URL in its entirety?

  Helpful if you have a single-page app and want to change the container's URL without reloading the entire page. Note that you'll have to listen to the `popstate` event on the embedding `window` to detect this navigation.

- `autoHeight`: Should the embedding `<iframe>` resize so that it matches the content of the currently loaded flow?

- `style`: CSS properties to be applied to the iframe container.

- `iframeTitle`: Optional string to set the iframe's title attribute for accessibility. If not provided, the embed will attempt to set a title from the flow's document title when available.

- `iframeAllow`: Optional string to set the iframe's allow attribute for permissions (for example: `"camera;"`).

- `authentication.idToken`: When the Flow requires an ID token, this can be used to provide it.

- `origin`: When present, loads the flow from your custom domain instead of the default formsort domain.

### `loadFlow(clientLabel: string, flowLabel: string, variantLabel?: string, queryParams?: Array<[string, string]>) => void`

Starts loading a Formsort variant, or a flow.

Note that `variantLabel` is optional. If it is not provided, a variant will be chosen from the flow:

- Based on weights, if weights are assigned

- At random, if no weights are assigned

### `unloadFlow() => void`

Remove inserted iFrame and all its event listeners.

### `setSize(width: number, height: number) => void`

Set the CSS size of the embed.

You may also style the embed's iframe using CSS - it is the iframe child of the `rootEl`, so you'd use the selector `#rootEl > iframe`.

### Event listeners

```ts
embed.addEventListener(eventName: key of IEventMap, fn: IEventMap[eventName]) => void
```

If the flow is embedded in a whitelisted domain, each event listener will be passed the user's answers.

The events include:

#### FlowLoaded `(answers?: { [key: string]: any } ) => void`

Set a callback function to be called when the Formsort flow has loaded completely.

Note that this is more accurate than listening for the iframe's `load` event, as this is sent from within the Formsort application code and not merely when the DOM is loaded.

You can listen for this to do things like hide the frame container, or display a loading indicator, until everything is loaded to ensure a seamless initial experience.

```ts
const embed = FormsortWebEmbed(document.body);
embed.addEventListener('FlowLoaded', () => {
  console.log('Flow has loaded!');
});
embed.loadFlow('formsort', 'onboarding', 'main');
```

#### FlowFinalized `(answers?: { [key: string]: any }) => void`

Set a callback to be called when the flow is complete, meaning the user has finished all of the steps available to them.

Useful for performing an action after the flow is complete, such as displaying a congratulations or starting a payment process.

#### FlowClosed `(answers?: { [key: string]: any }) => void`

Set a callback to be called when the user abandons the flow before finalizing it.

Note that this is only possible if your style set defines a close button.

#### StepLoaded `(answers?: { [key: string]: any }) => void`

Set a callback to be called when a new step is loaded.

This will happen once after the flow is loaded, if the user hasn't previously completed the flow. Subsequently, this event will happen following the completion of each step, except for the completion of the final step.

#### StepCompleted `(answers?: { [key: string]: any }) => void`

Set a callback to be called when a step is completed. This includes the completion of the final step, before the `"FlowFinalized"` event.

#### ResponderStateUpdated `(answers?: { [key: string]: any }) => void`

Set a callback to be called whenever the responder state is updated, corresponding to when Formsort itself saves responder answers and delivers them to integrations.

By default, this will correlate roughly to the `StepCompleted` event, since the default behavior is to save answers only when advancing between steps. However, if you have enabled [autoSave](https://docs.formsort.com/building-flows/variant-settings/additional-flow-settings#enable-autosave), then you will receive answers a short delay after a user has finished entering data.

#### redirect `({ url: string, answers?: { [key: string]: any } }) => ({ cancel?: boolean }) | undefined`

Set a callback to customize the way Formsort handles redirects. To cancel Formsort's handling of the redirect, return:

```typescript
{
  cancel: true;
}
```

If the callback does not return a value, Formsort will handle the redirect as usual.

This is helpful if you're embedding Formsort within a single-page app that has custom URL route handling.

#### unauthorized `() => void`

Set a callback for unauthorized Formsort messages.

This callback is used when the Formsort Flow is authenticated but the ID token is missing or invalid.

## Development

By default, the web embed accesses the production formsort servers. If you would like to point to another flow server, set `origin` in the config to the correct base URL, for example:

```ts
FormsortWebEmbed(document.body, { origin: 'http://localhost:4040' });
```