feat: improve LitElement identification

src/rules/lifecycle-super.ts

@@ -5,6 +5,7 @@
 
 import {Rule} from 'eslint';
 import * as ESTree from 'estree';
+import {isLitClass} from "../util";
 
 const methodNames = ['connectedCallback', 'disconnectedCallback', 'update'];
 
@@ -44,11 +45,7 @@
      * @return {void}
      */
     function classEnter(node: ESTree.Class): void {
-      if (
-        !node.superClass ||
-        node.superClass.type !== 'Identifier' ||
-        node.superClass.name !== 'LitElement'
-      ) {
+      if (!isLitClass(node)) {
         return;
       }
 

src/rules/no-property-change-update.ts

@@ -5,7 +5,7 @@
 
 import {Rule} from 'eslint';
 import * as ESTree from 'estree';
-import {getPropertyMap, PropertyMapEntry} from '../util';
+import {getPropertyMap, isLitClass, PropertyMapEntry} from '../util';
 
 const superUpdateQuery =
   'CallExpression' +
@@ -49,11 +49,7 @@ const rule: Rule.RuleModule = {
      * @return {void}
      */
     function classEnter(node: ESTree.Class): void {
-      if (
-        !node.superClass ||
-        node.superClass.type !== 'Identifier' ||
-        node.superClass.name !== 'LitElement'
-      ) {
+      if (!isLitClass(node)) {
         return;
       }
 

src/rules/no-this-assign-in-render.ts

@@ -5,6 +5,7 @@
 
 import {Rule} from 'eslint';
 import * as ESTree from 'estree';
+import {isLitClass} from "../util";
 
 //------------------------------------------------------------------------------
 // Rule Definition
@@ -38,11 +39,7 @@
      * @return {void}
      */
     function classEnter(node: ESTree.Class): void {
-      if (
-        !node.superClass ||
-        node.superClass.type !== 'Identifier' ||
-        node.superClass.name !== 'LitElement'
-      ) {
+      if (!isLitClass(node)) {
         return;
       }
 

src/test/rules/attribute-names_test.ts

@@ -125,6 +125,40 @@ ruleTester.run('attribute-names', rule, {
           messageId: 'casedPropertyWithoutAttribute'
         }
       ]
+    },
+    {
+      code: `@customElement('foo-bar')
+      class FooBar extends FooElement {
+        @property({ type: String })
+        camelCase = 'foo';
+      }`,
+      parser,
+      parserOptions,
+      errors: [
+        {
+          line: 4,
+          column: 9,
+          messageId: 'casedPropertyWithoutAttribute'
+        }
+      ]
+    },
+    {
+      code: `@foo
+      @customElement('foo-bar')
+      @bar
+      class FooBar extends FooElement {
+        @property({ type: String })
+        camelCase = 'foo';
+      }`,
+      parser,
+      parserOptions,
+      errors: [
+        {
+          line: 6,
+          column: 9,
+          messageId: 'casedPropertyWithoutAttribute'
+        }
+      ]
     }
   ]
 });

src/test/rules/lifecycle-super_test.ts

@@ -21,6 +21,14 @@ const ruleTester = new RuleTester({
   }
 });
 
+const parser = require.resolve('@babel/eslint-parser');
+const parserOptions = {
+  requireConfigFile: false,
+  babelOptions: {
+    plugins: [['@babel/plugin-proposal-decorators', {version: '2023-11'}]]
+  }
+};
+
 ruleTester.run('lifecycle-super', rule, {
   valid: [
     'class Foo { }',
@@ -184,6 +192,24 @@ ruleTester.run('lifecycle-super', rule, {
           column: 9
         }
       ]
+    },
+    {
+      code: `@customElement('foo')
+      class Foo extends FooElement {
+        connectedCallback() {
+          super.foo.connectedCallback();
+        }
+      }`,
+      parser,
+      parserOptions,
+      errors: [
+        {
+          messageId: 'callSuper',
+          data: {method: 'connectedCallback'},
+          line: 3,
+          column: 9
+        }
+      ]
     }
   ]
 });

src/test/rules/no-property-change-update_test.ts

@@ -228,6 +228,27 @@ ruleTester.run('no-property-change-update', rule, {
           column: 11
         }
       ]
+    },
+    {
+      code: `@customElement('foo')
+      class Foo extends FooElement {
+        static get properties() {
+          return { prop: { type: String } };
+        }
+        update(change) {
+          super.update();
+          this.prop = 'foo';
+        }
+      }`,
+      parser,
+      parserOptions,
+      errors: [
+        {
+          messageId: 'propertyChange',
+          line: 8,
+          column: 11
+        }
+      ]
     }
   ]
 });

src/test/rules/no-this-assign-in-render_test.ts

@@ -21,6 +21,14 @@ const ruleTester = new RuleTester({
   }
 });
 
+const parser = require.resolve('@babel/eslint-parser');
+const parserOptions = {
+  requireConfigFile: false,
+  babelOptions: {
+    plugins: [['@babel/plugin-proposal-decorators', {version: '2023-11'}]]
+  }
+};
+
 ruleTester.run('no-this-assign-in-render', rule, {
   valid: [
     'const x = 808;',
@@ -126,6 +134,23 @@ ruleTester.run('no-this-assign-in-render', rule, {
           column: 11
         }
       ]
+    },
+    {
+      code: `@customElement('foo')
+      class Foo extends FooElement {
+        render() {
+          this['prop'] = 'foo';
+        }
+      }`,
+      parser,
+      parserOptions,
+      errors: [
+        {
+          messageId: 'noThis',
+          line: 4,
+          column: 11
+        }
+      ]
     }
   ]
 });

src/util.ts

@@ -13,13 +13,39 @@ export type DecoratedNode = ESTree.Node & {
   decorators?: BabelDecorator[];
 };
 
+export type NodeWithParent = ESTree.Node & {
+  parent?: ESTree.Node;
+}
+
 /**
  * Returns if given node has a lit identifier
- * @param {ESTree.Node} node
+ * @param {NodeWithParent} node
  * @return {boolean}
  */
-function hasLitIdentifier(node: ESTree.Node): boolean {
-  return node.type === 'Identifier' && node.name === 'LitElement';
+function hasLitIdentifier(node: NodeWithParent): boolean {
+  if (node.type === 'Identifier' && node.name === 'LitElement') {
+    return true;
+  }
+
+  if (node.parent && node.parent.type === 'ClassDeclaration') {
+    const decoratedNode = node.parent as DecoratedNode;
+
+    if (!decoratedNode.decorators || !Array.isArray(decoratedNode.decorators)) {
+      return false;
+    }
+
+    for (const decorator of decoratedNode.decorators) {
+      if (
+        decorator.expression.type === 'CallExpression' &&
+        decorator.expression.callee.type === 'Identifier' &&
+        decorator.expression.callee.name === 'customElement'
+      ) {
+        return true;
+      }
+    }
+  }
+
+  return false;
 }
 
 /**