Move to PatternFly Elements and lit

PFE uses lit, so it makes sense to just use that for the main
application as well. Web components are pretty much React built into the
web platform, and lit adds some convenience around that.

This is mostly a demo -- for real Cockpit pages, PF Elements is still
missing too many components.

.eslintrc.json

@@ -4,12 +4,11 @@
         "browser": true,
         "es6": true
     },
-    "extends": ["eslint:recommended", "standard", "standard-jsx", "standard-react"],
+    "extends": ["eslint:recommended", "standard"],
     "parserOptions": {
         "ecmaVersion": "2022",
         "sourceType": "module"
     },
-    "plugins": ["react", "react-hooks"],
     "rules": {
         "indent": ["error", 4,
             {
@@ -22,23 +21,15 @@
         "no-var": "error",
         "lines-between-class-members": ["error", "always", { "exceptAfterSingleLine": true }],
         "prefer-promise-reject-errors": ["error", { "allowEmptyReject": true }],
-        "react/jsx-indent": ["error", 4],
         "semi": ["error", "always", { "omitLastInOneLineBlock": true }],
 
-        "react-hooks/rules-of-hooks": "error",
-        "react-hooks/exhaustive-deps": "error",
-
         "camelcase": "off",
         "comma-dangle": "off",
         "curly": "off",
         "jsx-quotes": "off",
         "key-spacing": "off",
         "no-console": "off",
         "quotes": "off",
-        "react/jsx-curly-spacing": "off",
-        "react/jsx-indent-props": "off",
-        "react/jsx-no-useless-fragment": "error",
-        "react/prop-types": "off",
         "space-before-function-paren": "off",
         "standard/no-callback-literal": "off"
     },

package.json

@@ -18,8 +18,6 @@
     "stylelint:fix": "stylelint --fix src/*{.css,scss}"
   },
   "devDependencies": {
-    "@types/react": "18.3.12",
-    "@types/react-dom": "18.3.1",
     "@typescript-eslint/eslint-plugin": "8.14.0",
     "argparse": "2.0.1",
     "esbuild": "0.24.0",
@@ -30,12 +28,9 @@
     "eslint": "8.57.1",
     "eslint-config-standard": "17.1.0",
     "eslint-config-standard-jsx": "11.0.0",
-    "eslint-config-standard-react": "13.0.0",
     "eslint-plugin-import": "2.31.0",
     "eslint-plugin-node": "11.1.0",
     "eslint-plugin-promise": "6.6.0",
-    "eslint-plugin-react": "7.37.2",
-    "eslint-plugin-react-hooks": "4.6.2",
     "gettext-parser": "8.0.0",
     "glob": "11.0.0",
     "htmlparser": "1.7.7",
@@ -50,11 +45,7 @@
     "typescript": "5.6.3"
   },
   "dependencies": {
-    "@patternfly/patternfly": "5.4.2",
-    "@patternfly/react-core": "5.4.8",
-    "@patternfly/react-icons": "5.4.2",
-    "@patternfly/react-styles": "5.4.1",
-    "react": "18.3.1",
-    "react-dom": "18.3.1"
+    "@patternfly/elements": "4.0.2",
+    "lit": "3.2.1"
   }
 }

packaging/cockpit-starter-kit.spec.in

@@ -57,7 +57,7 @@ appstream-util validate-relax --nonet %{buildroot}/%{_datadir}/metainfo/*
 
 %files
 %doc README.md
-%license LICENSE dist/index.js.LEGAL.txt dist/index.css.LEGAL.txt
+%license LICENSE dist/index.js.LEGAL.txt
 %{_datadir}/cockpit/*
 %{_datadir}/metainfo/*
 

src/app.tsx

@@ -1,7 +1,7 @@
 /*
  * This file is part of Cockpit.
  *
- * Copyright (C) 2017 Red Hat, Inc.
+ * Copyright (C) 2024 Red Hat, Inc.
  *
  * Cockpit is free software; you can redistribute it and/or modify it
  * under the terms of the GNU Lesser General Public License as published by
@@ -17,32 +17,36 @@
  * along with Cockpit; If not, see <http://www.gnu.org/licenses/>.
  */
 
-import React, { useEffect, useState } from 'react';
-import { Alert } from "@patternfly/react-core/dist/esm/components/Alert/index.js";
-import { Card, CardBody, CardTitle } from "@patternfly/react-core/dist/esm/components/Card/index.js";
+import { css, html, LitElement } from 'lit';
+import { customElement, state } from 'lit/decorators.js';
+
+import '@patternfly/elements/pf-card/pf-card.js';
 
 import cockpit from 'cockpit';
 
 const _ = cockpit.gettext;
 
-export const Application = () => {
-    const [hostname, setHostname] = useState(_("Unknown"));
+@customElement('ct-application')
+export class Application extends LitElement {
+    @state() private accessor hostname = _("Unknown");
+
+    static readonly styles = css`
+        .running-on {
+            color: green;
+        }
+    `;
 
-    useEffect(() => {
+    connectedCallback() {
+        super.connectedCallback();
         const hostname = cockpit.file('/etc/hostname');
-        hostname.watch(content => setHostname(content?.trim() ?? ""));
-        return hostname.close;
-    }, []);
-
-    return (
-        <Card>
-            <CardTitle>Starter Kit</CardTitle>
-            <CardBody>
-                <Alert
-                    variant="info"
-                    title={ cockpit.format(_("Running on $0"), hostname) }
-                />
-            </CardBody>
-        </Card>
-    );
-};
+        hostname.watch(content => { this.hostname = content?.trim() ?? "" });
+    }
+
+    render() {
+        return html`
+            <pf-card>
+                <h1 slot="header">Starter Kit</h1>
+                <p class="running-on">${cockpit.format(_("Running on $0"), this.hostname)}</p>
+            </pf-card>`;
+    }
+}

src/index.html

@@ -29,6 +29,6 @@
 </head>
 
 <body>
-    <div id="app"></div>
+    <ct-application />
 </body>
 </html>

src/index.tsx

@@ -1,7 +1,7 @@
 /*
  * This file is part of Cockpit.
  *
- * Copyright (C) 2017 Red Hat, Inc.
+ * Copyright (C) 2024 Red Hat, Inc.
  *
  * Cockpit is free software; you can redistribute it and/or modify it
  * under the terms of the GNU Lesser General Public License as published by
@@ -17,16 +17,6 @@
  * along with Cockpit; If not, see <http://www.gnu.org/licenses/>.
  */
 
-import React from 'react';
-import { createRoot } from 'react-dom/client';
+// import "cockpit-dark-theme"; // doesn't work for PFE
 
-import "cockpit-dark-theme";
-
-import { Application } from './app.jsx';
-
-import "patternfly/patternfly-5-cockpit.scss";
-import './app.scss';
-
-document.addEventListener("DOMContentLoaded", () => {
-    createRoot(document.getElementById("app")!).render(<Application />);
-});
+import './app.jsx';

test/browser/run-test.sh

@@ -7,6 +7,19 @@ git init
 rm -f bots  # common local case: existing bots symlink
 make bots test/common
 
+# support running from clean git tree
+if [ -e .git ]; then
+    # move package.json temporarily otherwise npm might try to install the dependencies from it
+    rm -f package-lock.json  # otherwise the command below installs *everything*, argh
+    mv package.json .package.json
+    # only install a subset to save time/space
+    npm install query-selector-shadow-dom
+    mv .package.json package.json
+else
+    # upstream tarballs ship test dependencies; print version for debugging
+    grep '"version"' node_modules/query-selector-shadow-dom/package.json
+fi
+
 # disable detection of affected tests; testing takes too long as there is no parallelization
 mv .git dot-git
 

test/check-application

@@ -18,16 +18,16 @@ class TestApplication(testlib.MachineCase):
 
         self.login_and_go("/starter-kit")
         # verify expected heading
-        b.wait_text(".pf-v5-c-card__title", "Starter Kit")
+        b.wait_text("pf-card [slot='header']", "Starter Kit")
 
         # verify expected host name
         hostname = m.execute("cat /etc/hostname").strip()
-        b.wait_in_text(".pf-v5-c-alert__title", "Running on " + hostname)
+        b.wait_in_text("pf-card .running-on", "Running on " + hostname)
 
         # change current hostname
         self.write_file("/etc/hostname", "new-" + hostname)
         # verify new hostname name
-        b.wait_in_text(".pf-v5-c-alert__title", "Running on new-" + hostname)
+        b.wait_in_text("pf-card .running-on", "Running on new-" + hostname)
 
         # change language to German
         b.switch_to_top()
@@ -46,7 +46,7 @@ class TestApplication(testlib.MachineCase):
         b.go("/starter-kit")
         b.enter_page("/starter-kit")
         # page label (from js) should be translated
-        b.wait_in_text(".pf-v5-c-alert__title", "Läuft auf")
+        b.wait_in_text("pf-card .running-on", "Läuft auf")
 
 
 if __name__ == '__main__':

tsconfig.json

@@ -3,7 +3,6 @@
     "allowJs": true,
     "checkJs": true,
     "exactOptionalPropertyTypes": true,
-    "jsx": "react",
     "lib": [
       "dom",
       "es2020"