A plug is a self-contained JavaScript bundle (*.plug.js) that extends SilverBullet. It runs inside a sandboxed Web Worker, talks to the editor via API|syscalls, and hooks into SilverBullet through commands, events, slash commands, message queues, and more.

A big chunk of SilverBullet itself is implemented as a mix of Space Lua and built-in plugs, so it’s also worth exploring built-in plugs source code to get a feel for how things work.

This section covers the basics to build, test, and distribute your own plug:

• Plugs/Development/Architecture: how plugs are loaded, executed, and sandboxed
• Plugs/Development/Reference: *.plug.yaml manifests, hook types, and the syscall catalog
• Plugs/Development/Distribution and Testing: packaging a plug as a Library, testing, debugging

Quick start

The easiest way to start is to click the “Use this template” button on the silverbullet-plug-template repo. Then:

npm install
npm run build

This produces a yourplug.plug.js bundle. For development, copy somewhere in your Space (it doesn’t really matter where):

cp yourplug.plug.js ~/myspace/

Within a few seconds watch your browser’s JavaScript console — the plug file should be synced locally. You can now run the Plugs: Reload command to “hot” reload it, without a full page.

Hello world

A minimal plug consists of two files: a YAML manifest and the TypeScript source it references.

hello.plug.yaml

name: hello
functions:
  helloCommand:
    path: "./hello.ts:helloCommand"
    command:
      name: "Hello: World"

hello.ts

import { editor } from "@silverbulletmd/silverbullet/syscalls";

export async function helloCommand() {
  await editor.flashNotification("Hello, world!");
}

Build, copy into your space, plug reload, and a Hello: World should now be available as a command from the Command Palette. When it’s run you should see a “Hello world!” message flash.

From here, read Plugs/Development/Architecture to understand what’s happening under the hood, then Plugs/Development/Reference for the full manifest/hook/syscall surface.