adobe-cep-polyfill

Polyfills the CEPEngine global variables―allowing your plugin to run in the browser.

Installation

Available on NPM as adobe-cep-polyfill:

npm i adobe-cep-polyfill

Usage

import polyfill from "adobe-cep-polyfill";

polyfill();

Usage Details

adobe-cep-polyfill exports a function that when executed will polyfill window.__adobe_cep__ and window.cep, if it's not defined. This means it is safe to call inside of your plugin without conflict―When executed within a CEP context, it will do nothing.

Note: The polyfill function should be executed before you instantiate CSInterface.

Mocking ExtendScript / evalScript

Running this polyfill allows most of CSInterace methods to be called without an error. But, if your plugin is reliant on data returned from an evalScript call it may be stuck in some bad state.

To get around that, the polyfill'd evalScript will check the window for a key matching your evalScript.

This allows you to write functions that mock your host scripts. The functions should return JSON.stringified objects.

Basic Example

import polyfill from "adobe-cep-polyfill";

polyfill();

const cs = new CSInterface();


// you can load this in a separate script file, and/or before instantiating CSInterface
// or however you please―as long as it is called before the cs.evalScript is called.
window.addTwoNumbers = (x, y) => {
  // needs to be a JSON stringifiedresult
  return JSON.stringify({ result: x + y  });
};

// ... some time later

cs.evalScript("addTwoNumbers(2, 3)", (response) => {
  const result = JSON.parse(response); // 5
});

Real World Example

You can view a real example here: @Fuse Fonts/plugin.host-scripts.mjs.

Context: The Fuse Fonts plugin loads the list of fonts available on the device. So, the mock function loads a list of fonts from Google Web Fonts instead.

Which powers this demo page: Fuse Fonts Web Demo

Advanced Usage

This polyfill is fairly approachable, and isn't doing anything complex. You can view the source and get an idea of everything it's doing pretty quickly: index.js

Contributing

Tests

The tests focus is on being able to instantiate CSInterface, as well as call any methods.

Tests setup

Before running tests we need to:

• transform our es6 module into a require-able common js format
• download CSInterface.js (from Adobe CEP Resources repo)

These are both accomplished for you via:

npm run test:setup

Running Tests

Run tests the standard npm package way:

npm run test