Adds a devtools panel to the browser that reads the inspected page.
npx extension@latest create my-devtools-typescript --template devtools-typescript
cd my-devtools-typescript
npm install
npm run dev!Powered by Extension.js
Adds a devtools panel to the browser that reads the inspected page.
What you'll see: A new Example tab inside the browser developer tools. The panel shows the title of the page you are inspecting.
How it works: A devtools extension is two pages, not one. The manifest points devtools_page at src/devtools/index.html, a registrar the browser loads in the background whenever devtools opens. That page has no visible UI at all, and its only job is one call to chrome.devtools.panels.create('Example', '', 'panel/index.html'). The second page, bundled from src/panel/, is the UI that call registers, and it is what shows up as the Example tab. Putting the UI in the registrar is the usual mistake, because nothing there is ever rendered.
The panel reads the inspected page through chrome.devtools.inspectedWindow.eval and renders one fact from it, the inspected document's title. That API works in every host, so the panel has something honest to show anywhere it loads. The panel also guards on chrome?.devtools?.inspectedWindow, because that namespace only exists when the page runs as a real panel. Opened as an ordinary extension page it renders a short message instead of throwing.
TypeScript adds one more check on top of that. inspectedWindow.eval hands the callback whatever the page expression produced, so the panel types the result as unknown and narrows it to a string before writing it to the DOM.
npx extension@latest create my-devtools-typescript --template devtools-typescript
cd my-devtools-typescript
npm install
npm run devA fresh browser window opens with the extension already loaded. Open the developer tools and pick the Example tab.
src/
├── devtools/
│ ├── index.html
│ └── scripts.ts
├── images/
│ ├── icon.png
│ └── typescript.png
├── panel/
│ ├── index.html
│ ├── scripts.ts
│ └── styles.css
└── manifest.jsonCloned this repo instead? The examples ship without npm scripts, so run Extension.js directly from the example directory. Run npm install first when the example declares dependencies.
Run the extension in development mode. Target a browser with --browser:
npx extension@latest dev . # Chromium (default)
npx extension@latest dev . --browser=chrome
npx extension@latest dev . --browser=edge
npx extension@latest dev . --browser=firefoxBuild for production:
npx extension@latest build . # Chromium (default)
npx extension@latest build . --browser=firefox
npx extension@latest build . --browser=edgePreview the production build with the bundled browser:
npx extension@latest preview .This template ships an end-to-end check (template.spec.ts) validated by the examples-repo CI on every commit.