SDK JS

What is it?

The GreyCat JS SDK is the official JavaScript (and TypeScript) library used by applications to communicate with a GreyCat Server.

This library is packaged as a platform agnostic bundle, meaning that is does not require to be run in a browser environment. It is compatible with Node.js (and Bun, deno) and all major Web browsers.

It is available as an ESM re-export from @greycat/web under: @greycat/web/sdk

Note that @greycat/sdk is the core protocol package that communicates with GreyCat. If you want to use the GreyCat WebComponents, you need to install @greycat/web which depends on this package.

Getting started

touch package.json

Then paste the following content in package.json:

{
  "name": "greycat-app",
  "version": "1.0.0",
  "main": "index.js",
  "type": "module",
  "dependencies": {
    "@greycat/web": "https://get.greycat.io/files/sdk/web/testing/7.0/7.0.0-testing.tgz"
  }
}

And install the dependency with:

npm i

First steps

Create a GreyCat project file named project.gcl with the following content:

@expose
fn hello(name: String): String {
  return "Hello, ${name}";
}

And start the server with this command:

greycat serve --user=1

--user=1 means that every requests are impersonated to be the root user, effectively bypassing authentication as this is out of the scope of this intro.

Create a JavaScript entry point file named index.js, paste the following:

import '@greycat/web/sdk';

// Initialize the connection with GreyCat using the defaults
await gc.sdk.init();

// Call an @expose'd function
const hello = await gc.project.hello(', world!');

// Say hello!
console.log(hello);

And run that file using Node.js:

node index.js
# Hello, world!

If you see Hello, world! in the console, you effectively used the JS SDK to communicate with a remote GreyCat server.