Extract rule: template-no-dynamic-subexpression-invocations

README.md

@@ -189,14 +189,15 @@ rules in templates can be disabled with eslint directives with mustache or html
 
 ### Best Practices
 
-| Name                                                                                             | Description                                               | 💼 | 🔧 | 💡 |
-| :----------------------------------------------------------------------------------------------- | :-------------------------------------------------------- | :- | :- | :- |
-| [template-builtin-component-arguments](docs/rules/template-builtin-component-arguments.md)       | disallow setting certain attributes on builtin components |    |    |    |
-| [template-no-action-modifiers](docs/rules/template-no-action-modifiers.md)                       | disallow usage of {{action}} modifiers                    |    |    |    |
-| [template-no-arguments-for-html-elements](docs/rules/template-no-arguments-for-html-elements.md) | disallow @arguments on HTML elements                      |    |    |    |
-| [template-no-array-prototype-extensions](docs/rules/template-no-array-prototype-extensions.md)   | disallow usage of Ember Array prototype extensions        |    |    |    |
-| [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                             |    |    |    |
+| Name                                                                                                         | Description                                               | 💼 | 🔧 | 💡 |
+| :----------------------------------------------------------------------------------------------------------- | :-------------------------------------------------------- | :- | :- | :- |
+| [template-builtin-component-arguments](docs/rules/template-builtin-component-arguments.md)                   | disallow setting certain attributes on builtin components |    |    |    |
+| [template-no-action-modifiers](docs/rules/template-no-action-modifiers.md)                                   | disallow usage of {{action}} modifiers                    |    |    |    |
+| [template-no-arguments-for-html-elements](docs/rules/template-no-arguments-for-html-elements.md)             | disallow @arguments on HTML elements                      |    |    |    |
+| [template-no-array-prototype-extensions](docs/rules/template-no-array-prototype-extensions.md)               | disallow usage of Ember Array prototype extensions        |    |    |    |
+| [template-no-debugger](docs/rules/template-no-debugger.md)                                                   | disallow {{debugger}} in templates                        |    |    |    |
+| [template-no-dynamic-subexpression-invocations](docs/rules/template-no-dynamic-subexpression-invocations.md) | disallow dynamic subexpression invocations                |    |    |    |
+| [template-no-log](docs/rules/template-no-log.md)                                                             | disallow {{log}} in templates                             |    |    |    |
 
 ### Components
 

docs/rules/template-no-dynamic-subexpression-invocations.md

@@ -0,0 +1,62 @@
+# ember/template-no-dynamic-subexpression-invocations
+
+<!-- end auto-generated rule header -->
+
+Disallow dynamic helper invocations.
+
+Dynamic helper invocations (where the helper name comes from a property or argument) make code harder to understand and can have performance implications. Use explicit helper names instead.
+
+## Rule Details
+
+This rule disallows invoking helpers dynamically using `this` or `@` properties.
+
+## Examples
+
+### Incorrect ❌
+
+```gjs
+<template>
+  {{(this.helper "arg")}}
+</template>
+```
+
+```gjs
+<template>
+  {{(@helperName "value")}}
+</template>
+```
+
+```gjs
+<template>
+  {{this.formatter this.data}}
+</template>
+```
+
+### Correct ✅
+
+```gjs
+<template>
+  {{format-date this.date}}
+</template>
+```
+
+```gjs
+<template>
+  {{(upper-case this.name)}}
+</template>
+```
+
+```gjs
+<template>
+  {{this.formattedData}}
+</template>
+```
+
+## Related Rules
+
+- [template-no-implicit-this](./template-no-implicit-this.md)
+
+## References
+
+- [Ember Guides - Template Helpers](https://guides.emberjs.com/release/components/helper-functions/)
+- [eslint-plugin-ember template-no-dynamic-subexpression-invocations](https://github.com/ember-cli/eslint-plugin-ember/blob/master/docs/rules/template-no-dynamic-subexpression-invocations.md)

lib/rules/template-no-dynamic-subexpression-invocations.js

@@ -0,0 +1,59 @@
+/** @type {import('eslint').Rule.RuleModule} */
+module.exports = {
+  meta: {
+    type: 'problem',
+    docs: {
+      description: 'disallow dynamic subexpression invocations',
+      category: 'Best Practices',
+      strictGjs: true,
+      strictGts: true,
+      url: 'https://github.com/ember-cli/eslint-plugin-ember/tree/master/docs/rules/template-no-dynamic-subexpression-invocations.md',
+    },
+    fixable: null,
+    schema: [],
+    messages: {
+      noDynamicSubexpressionInvocations:
+        'Do not use dynamic helper invocations. Use explicit helper names instead.',
+    },
+  },
+
+  create(context) {
+    return {
+      GlimmerSubExpression(node) {
+        // Check if the path is dynamic (contains @ or this)
+        if (
+          node.path &&
+          node.path.type === 'GlimmerPathExpression' &&
+          (node.path.head?.type === 'AtHead' ||
+            node.path.head?.type === 'ThisHead' ||
+            node.path.parts?.length > 0)
+        ) {
+          // If it's not a simple identifier, it's dynamic
+          if (node.path.head?.type === 'AtHead' || node.path.head?.type === 'ThisHead') {
+            context.report({
+              node,
+              messageId: 'noDynamicSubexpressionInvocations',
+            });
+          }
+        }
+      },
+      GlimmerMustacheStatement(node) {
+        // Check for dynamic invocations in mustache statements
+        if (
+          node.path &&
+          node.path.type === 'GlimmerPathExpression' &&
+          node.params &&
+          node.params.length > 0
+        ) {
+          // If the helper name starts with @ or this, it's dynamic
+          if (node.path.head?.type === 'AtHead' || node.path.head?.type === 'ThisHead') {
+            context.report({
+              node,
+              messageId: 'noDynamicSubexpressionInvocations',
+            });
+          }
+        }
+      },
+    };
+  },
+};

tests/lib/rules/template-no-dynamic-subexpression-invocations.js

@@ -0,0 +1,48 @@
+const rule = require('../../../lib/rules/template-no-dynamic-subexpression-invocations');
+const RuleTester = require('eslint').RuleTester;
+
+const ruleTester = new RuleTester({
+  parser: require.resolve('ember-eslint-parser'),
+  parserOptions: { ecmaVersion: 2022, sourceType: 'module' },
+});
+
+ruleTester.run('template-no-dynamic-subexpression-invocations', rule, {
+  valid: [
+    '<template>{{format-date this.date}}</template>',
+    '<template>{{(upper-case this.name)}}</template>',
+    '<template>{{helper "static"}}</template>',
+  ],
+
+  invalid: [
+    {
+      code: '<template>{{(this.helper "arg")}}</template>',
+      output: null,
+      errors: [
+        {
+          message: 'Do not use dynamic helper invocations. Use explicit helper names instead.',
+          type: 'GlimmerSubExpression',
+        },
+      ],
+    },
+    {
+      code: '<template>{{(@helperName "value")}}</template>',
+      output: null,
+      errors: [
+        {
+          message: 'Do not use dynamic helper invocations. Use explicit helper names instead.',
+          type: 'GlimmerSubExpression',
+        },
+      ],
+    },
+    {
+      code: '<template>{{this.formatter this.data}}</template>',
+      output: null,
+      errors: [
+        {
+          message: 'Do not use dynamic helper invocations. Use explicit helper names instead.',
+          type: 'GlimmerMustacheStatement',
+        },
+      ],
+    },
+  ],
+});