motiondeveloper / expression-globals-typescript

A library providing types for expressions, as well as for mocking the API (such as thisLayer and comp())

expression-globals-typescript

This library mocks the After Effects expressions API in TypeScript, providing types and the available global functions and variables.

To be used with rollup-plugin-ae-jsx, which will convert the code to After Effects friendly .jsx files and remove the globals imported from this package.

Usage

1. Install

   npm install expression-globals-typescript --save-dev

   Found in our Expressions Library Template.

2. Import classes to create layer, comp, and property mocks

   import { Property, Layer, Comp } from "expression-globals-typescript";
   
   const thisProperty = new Property<string>("Property value");
   const thisLayer = new Layer();
   const thisComp = new Comp();

   You can then use the properties and methods of these objects as you would within expressions.

   The Property constructor function takes a value and type (<>) for the value of the Property.

3. Import types

   This package makes available After Effects specific types, such as Color, Vector and more. See src/index.ts for the available types.

   import { Color, Vector, Value } from "expression-globals-typescript";

Why?

When writing expressions in Typescript using our Expressions Library Template and rollup-plugin-ae-jsx, TypeScript will complain if you try to use the global functions and objects available in expressions.

This is because they aren't defined in the development environment.

expression-globals-typescript solves this by mocking the entire expressions API in TypeScript, so you can import and use these globals, with the advantages of them being fully typed.