npm package: @financial-times/ads-embed
Description: Facilitate communication between advertising creatives in iframes and the main o-ads library via post message 
Author: Alex Florisca
Latest version: 7.4.0

# ads-embed

This module facilitates communication between advertising creatives in iframes and the `@financial-times/ads-legacy-o-ads` library via post message.
It requires an instance of `ads-legacy-o-ads`'s module to be existing in the top window to listen for the message.

This module is designed to be included in advertising creatives and not installed as a dependency.

## Touch Events
On touch screen devices touch events are captured by iframes and not passed on to the parent page, this can be an issue under some circumstances such as an ad included in a gallery where swiping is required to move forwards.

To mitigate these circumstances `ads-embed` will detect when a touch screen is present and post the `touchstart`, `touchend` and `touchmove` events to `ads-legacy-o-ads` via post message. You can listen for `oAds.touch` events in the top window if you need to react to these events.

## Usage

### Initialising

In a creative wrapper, include the following:

```
<script src="https://www.ft.com/__origami/service/build/v3/bundles/js?components=o-ads-embed@^3.0.0&system_code=advertising"></script>
if (window !== window.top) {
	window.Origami['o-ads-embed'].init();
}
```

### Collapsing

In a creative in DFP, include the following:

```
<div data-o-ads-collapse></div>
<script src="https://www.ft.com/__origami/service/build/v3/bundles/js?components=o-ads-embed@^3.0.0&system_code=advertising"></script>
if (window !== window.top) {
	window.Origami['o-ads-embed'].init();
}
```

This will collapse any ad slot that serves the creative with this code inside it.


### Send a 'slotClass' message

Since v4 `ads-embed` will send a postMessage to the `top` browsing context (usually the main window in a production setup) whenever an html element is found in its browsing context (i.e. the creative wrapper) that contains a `data-o-ads-class` attribute.

The postMessage will contain an object containing `type: "oAds.slotClass"`. Additionally it will contain a property `slotClass` with the value of the `data-o-ads-class` attribute.

Example:

If the creative wrapper contains an element like this `<div data-o-ads-class="sticky"></div>`, a postMessage will  be sent with a payload object like this:

```js
{
  type: "oAds.slotClass",
  slotClass: "sticky"
}
```
# Developers

## Demos

There are two demos that demonstrate the two uses mentioned above. In order to get things running, you'll need to add the following lines at the bottom of `main.js` and run `obt build`.

```
window.Origami = {
	'o-ads-embed': oAdsEmbed
}
```

The reason for this is that in a creative wrapper, we would load o-ads-embed through the Origami registry, which places a global `Origmai` object on the page with all of the modules requested. When we run the demos, we simply include a built version of the module from `/build/main.js`.

Run the demo with `obt demo --runServer`. 

Run the o-ads demos alongside (`npm run demo-server`), then visit http://localhost:3002/demos/local/o-ads-embed.html. You should see both the o-ads-embed demos load up in iframes on this page.