gnh1201/welsonjs

What is WelsonJS?

WelsonJS is a Windows‑only JavaScript framework that lets you write desktop applications (both console‑style and GUI‑style) with the languages that run on the built‑in Windows Script Host (cscript/wscript) engine. It bundles a set of transpilers (TypeScript, CoffeeScript, ReScript, LiveScript) and a rich set of libraries so you can develop, package, and run apps without installing any external runtime like Node.js.

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Key ideas

Idea	What it means
Runs on the native Windows ECMAScript engine	Your code is executed by the JavaScript engine that ships with Windows, so no extra runtime is required.
Self‑contained apps	An app can be distributed as a zip or an executable‑like .js file that the WelsonJS launcher runs, similar to a native Windows program.
Legacy‑friendly	Works on Windows XP SP3 and later, making it useful for older corporate environments where modern runtimes are unavailable.
Built‑in UI support	You can write GUI apps using an HTA (HTML Application) wrapper, letting you combine HTML/CSS/JS with the Windows UI.
Extensive library bundle	Includes jQuery, Monaco editor, React, many polyfills (core‑js, json2, yaml), CSS frameworks, and even native modules for Windows services, screen capture, virtual mouse/keyboard, and ESENT database access.
AI add‑ons	Optional connectors to ChatGPT, Google Gemini, Azure AI services, and other LLM APIs are pre‑wired into the launcher.
Packaging & deployment	Provides a launcher that manages instances, a PowerShell bootstrap script, Inno Setup templates, and a zip‑based distribution model.

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Typical use cases

• Automation on legacy PCs – run scripts that interact with Office, the file system, or Windows services where installing Node.js is impossible.
• Embedded or resource‑constrained tools – lightweight execution with no extra binaries, suitable for industrial controllers or thin‑client machines.
• Security‑sensitive environments – the framework isolates script execution and can operate without network access, while still offering optional AI services when needed.
• Office‑centric apps – automate Excel, Word, Outlook, etc., using familiar JavaScript syntax.
• Prototyping Windows GUIs – build HTA‑based windows with HTML/CSS and ship them as a single package.

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Quick start (from the README)

1. Create a module – lib/sayhello.js

   function say() { console.log("hello"); }
   exports.say = say;
   

2. Create an entry script – sayhello.js

   var SayHello = require("lib/sayhello");
   function main() {
       console.log("calling say()");
       SayHello.say();
       console.log("ended say()");
   }
   exports.main = main;
   

3. Run it from the console

   cscript app.js sayhello
   

   Output:

   calling say()
   hello
   ended say()
   

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How to ship an app

• Zip + Launcher – bundle your source files, zip them, and distribute the zip together with the WelsonJS launcher.
• Inno Setup installer – a ready‑made setup.iss script is provided.
• PowerShell bootstrap – irm https://catswords.blob.core.windows.net/welsonjs/bootstrap.ps1 | iex pulls the runtime and runs your code.
• Plain copy – just copy the folder to the target machine.

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Notable integrations

• LLM services – ChatGPT, Google Gemini, Azure AI Services can be called from within a WelsonJS script.
• Windows‑specific native module (WelsonJS.ManagedObject) – service control, window handling, bitmap manipulation, virtual input, shared‑memory IPC.
• Database – wrapper for the built‑in ESENT (Extensible Storage Engine) database.
• DevTools – Chrome DevTools Protocol, ADB support, gRPC/JSON‑RPC clients, various HTTP utilities (cURL, BITS, certutil).
• Other APIs – AviationStack, SerpApi flight data, VMware OVFTool, SEO/ SERP tools.

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Where to get it

• Launcher download – https://catswords.blob.core.windows.net/welsonjs/welsonjs_launcher_latest.zip
• PowerShell bootstrap – irm https://catswords.blob.core.windows.net/welsonjs/bootstrap.ps1 | iex
• Community – Discord, Teams, ActivityPub, XMPP, and a public Discord server are linked from the README.

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Who’s behind it

The project is maintained by gnh1201 (Catswords) and is sponsored through GitHub Sponsors, Liberapay, and Buy‑Me‑A‑Coffee. It lists a number of corporate collaborators (SerpApi, Microsoft ISV program, Tenstorrent, etc.) and has been featured in several newsletters and tech blogs.

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Bottom line

WelsonJS is a real, open‑source framework for building Windows desktop applications using only the JavaScript engine that ships with Windows. It is especially useful when you need to run JavaScript on legacy or highly locked‑down Windows machines, and it also offers optional AI service hooks for modern generative‑AI use cases.