Typed Photoshop ExtendScript

TypeScript typings for Photoshop ExtendScript.

Installation

yarn add -D https://github.com/fsjohnhuang/typed-photoshop.git

or

npm install --save-dev https://github.com/fsjohnhuang/typed-photoshop.git

Include Declaration Files

Because this repository is not sub-project of DefinitelyTyped project yet, you have to include the declaration files manually in two ways.

1. Add a types reference.

/// <reference types="typed-photoshop"/>

app.load(File("/path/to/image.tif"))
alert(activeDocument.channels)
app.close()

2. Add ./node_modules/typed-photoshop to compilerOptions.typeRoot property in tsconfig.json.

{
    "compilerOptions": {
        "typeRoot": ["./node_modules/@types", "./node_modules/typed-photoshop"] 
    }
}

app.load(File("/path/to/image.tif"))
alert(activeDocument.channels)
app.close()

Recommendation

Polyfill

Since ExtendScript is based on ES3, there is no built-in Array.prototype.map method and other modern JavaScript APIs for you. core-js is a powerful and widely used polyfill library, but it's a sad story that errors occur while it's running on ExtendScript engine. Fortunately, es5-shim does work fine.

Meanwhile json2 helps us to fit the pain from the lack of native JSON support.

Installation

yarn add es5-shim json2

or

npm install es5-shim json2 --save

Usage

import 'es5-shim'
import 'json2'
// import polyfill library in main.ts file.

Object Notes

Because it's impossible to emulate property descriptors in ES3 engine, the following functions are just mocks and you should avoid to use them if possible, only shim thirdparty library. defineProperty and defineProperties Supports only Data Descriptor. Writable, Enumerable and Configurable properties of descriptor are ignored. If you try to define set or get property, there is an error thrown. getOwnPropertyDescriptor Supports only Data Descriptor. Configurable property of descriptor is always TRUE. Writable and Enumerable will be always TRUE on user defined objects, but may vary on built-ins. freeze, preventExtensions and seal Only validate input parameter and return the input if it is an object. isExtensible, isFrozen and isSealed If the input parameter is an object, returns TRUE, FALSE and FALSE respectively.

The following functions could be used in our code. getOwnPropertyNames The function uses reflection interface which are provided by ExtendScript. It gets the own properties of an object no matter enumerable or not. But there is no guarantee to the order of enumeration is the same as in the for in loop statement. keys Used in the for in loop statement along with getOwnProperty function to get own enumerable properties of an object. getPrototypeOf Return the built-in __proto__ property of an object.

tsconfig.json

1. Set compilerOptions/target to ES3 to avoiding errors caused by Object.defineProperty running in ExtendScript engine;
2. Because the default setting of compilerOptions/lib includes DOM whose File definition is different from that in ExtendScript totally, set compilerOptions/lib to ["ES3"] or ["ES5"] please.