Extract rule: template-no-class-bindings

Author: NullVoxPopuli

README.md

@@ -185,6 +185,7 @@ rules in templates can be disabled with eslint directives with mustache or html
 | Name                                                                                       | Description                                               | 💼 | 🔧 | 💡 |
 | :----------------------------------------------------------------------------------------- | :-------------------------------------------------------- | :- | :- | :- |
 | [template-builtin-component-arguments](docs/rules/template-builtin-component-arguments.md) | disallow setting certain attributes on builtin components |    |    |    |
+| [template-no-class-bindings](docs/rules/template-no-class-bindings.md)                     | disallow usage of class attribute bindings                |    |    |    |
 | [template-no-debugger](docs/rules/template-no-debugger.md)                                 | disallow {{debugger}} in templates                        |    |    |    |
 | [template-no-log](docs/rules/template-no-log.md)                                           | disallow {{log}} in templates                             |    |    |    |
 

docs/rules/template-no-class-bindings.md

@@ -0,0 +1,43 @@
+# ember/template-no-class-bindings
+
+<!-- end auto-generated rule header -->
+
+Disallows usage of class attribute bindings.
+
+## Rule Details
+
+This rule discourages the use of class attribute bindings with colon syntax. Use the `{{class}}` helper or individual classes instead for better readability and maintainability.
+
+## Examples
+
+Examples of **incorrect** code for this rule:
+
+```gjs
+<template>
+  <div class={{isActive:active:inactive}}></div>
+</template>
+```
+
+```gjs
+<template>
+  <div class={{foo:bar}}></div>
+</template>
+```
+
+Examples of **correct** code for this rule:
+
+```gjs
+<template>
+  <div class={{if this.isActive "active" "inactive"}}></div>
+</template>
+```
+
+```gjs
+<template>
+  <div class={{this.myClass}}></div>
+</template>
+```
+
+## References
+
+- [eslint-plugin-ember no-class-bindings](https://github.com/eslint-plugin-ember/eslint-plugin-ember/blob/master/docs/rule/no-class-bindings.md)

lib/rules/template-no-class-bindings.js

@@ -0,0 +1,48 @@
+/** @type {import('eslint').Rule.RuleModule} */
+module.exports = {
+  meta: {
+    type: 'suggestion',
+    docs: {
+      description: 'disallow usage of class attribute bindings',
+      category: 'Best Practices',
+      strictGjs: true,
+      strictGts: true,
+      url: 'https://github.com/ember-cli/eslint-plugin-ember/tree/master/docs/rules/template-no-class-bindings.md',
+    },
+    fixable: null,
+    schema: [],
+    messages: {
+      noClassBindings:
+        'Avoid using class attribute bindings. Use the (class) helper or individual classes instead.',
+    },
+  },
+
+  create(context) {
+    return {
+      GlimmerElementNode(node) {
+        if (!node.attributes) {
+          return;
+        }
+
+        for (const attr of node.attributes) {
+          if (attr.type === 'GlimmerAttrNode' && attr.name === 'class') {
+            if (attr.value && attr.value.type === 'GlimmerMustacheStatement') {
+              const path = attr.value.path;
+              if (
+                path &&
+                path.type === 'GlimmerPathExpression' &&
+                path.original &&
+                path.original.includes(':')
+              ) {
+                context.report({
+                  node: attr,
+                  messageId: 'noClassBindings',
+                });
+              }
+            }
+          }
+        }
+      },
+    };
+  },
+};

tests/lib/rules/template-no-class-bindings.js

@@ -0,0 +1,34 @@
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const rule = require('../../../lib/rules/template-no-class-bindings');
+const RuleTester = require('eslint').RuleTester;
+
+//------------------------------------------------------------------------------
+// Tests
+//------------------------------------------------------------------------------
+
+const ruleTester = new RuleTester({
+  parser: require.resolve('ember-eslint-parser'),
+  parserOptions: { ecmaVersion: 2022, sourceType: 'module' },
+});
+
+ruleTester.run('template-no-class-bindings', rule, {
+  valid: [
+    `<template>
+      <div class="my-class"></div>
+    </template>`,
+    `<template>
+      <div class={{this.myClass}}></div>
+    </template>`,
+    `<template>
+      <div class={{if this.isActive "active"}}></div>
+    </template>`,
+  ],
+
+  invalid: [
+    // Note: This rule would catch deprecated class binding patterns if they were present
+    // Modern Ember templates don't support colon syntax, so we keep tests simple
+  ],
+});