// YAPF image preview for VS Code — a read-only custom editor for *.yapf.
// Copyright 2026 Nexoniarz — Apache License 2.0.
const vscode = require('vscode');
class YapfPreviewProvider {
constructor(context) { this.context = context; }
openCustomDocument(uri) { return { uri, dispose() {} }; }
async resolveCustomEditor(document, panel) {
const media = vscode.Uri.joinPath(this.context.extensionUri, 'media');
panel.webview.options = { enableScripts: true, localResourceRoots: [media] };
panel.webview.html = this.html(panel.webview, media);
const send = async () => {
try {
const bytes = await vscode.workspace.fs.readFile(document.uri);
panel.webview.postMessage({ type: 'file', name: document.uri.path.split('/').pop(), bytes });
} catch (e) {
panel.webview.postMessage({ type: 'error', message: String(e.message || e) });
}
};
panel.webview.onDidReceiveMessage((m) => { if (m.type === 'ready') send(); });
// Reload when the file changes on disk.
const folder = vscode.Uri.joinPath(document.uri, '..');
const name = document.uri.path.split('/').pop();
const watcher = vscode.workspace.createFileSystemWatcher(new vscode.RelativePattern(folder, name));
watcher.onDidChange(send);
panel.onDidDispose(() => watcher.dispose());
}
html(webview, media) {
const uri = (f) => webview.asWebviewUri(vscode.Uri.joinPath(media, f));
const nonce = Math.random().toString(36).slice(2) + Date.now().toString(36);
return `
YAPF Preview
Loading…
`;
}
}
function activate(context) {
context.subscriptions.push(vscode.window.registerCustomEditorProvider(
'yapf.preview', new YapfPreviewProvider(context),
{ webviewOptions: { retainContextWhenHidden: true }, supportsMultipleEditorsPerDocument: true }));
}
function deactivate() {}
module.exports = { activate, deactivate };