feat(eslint): cover private methods

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot-Session: 8ebd5bf2-c44b-42d5-be25-e7936d4b0a14
Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: 2 people

common/changes/@rushstack/eslint-config/native-private-fields_2026-08-18-12-00-00.json

@@ -2,7 +2,7 @@
   "changes": [
     {
       "packageName": "@rushstack/eslint-config",
-      "comment": "Enable the rule that prefers ECMAScript private class fields.",
+      "comment": "Enable the rule that prefers ECMAScript private class members.",
       "type": "minor"
     }
   ]

common/changes/@rushstack/eslint-plugin/native-private-fields_2026-08-18-12-00-00.json

@@ -2,7 +2,7 @@
   "changes": [
     {
       "packageName": "@rushstack/eslint-plugin",
-      "comment": "Add a rule that requires ECMAScript private class fields instead of TypeScript private fields.",
+      "comment": "Add a rule that requires ECMAScript private syntax for class fields, methods, and accessors.",
       "type": "minor"
     }
   ]

eslint/eslint-config/flat/profile/_common.js

@@ -221,7 +221,7 @@ const commonConfig = [
       '@rushstack/no-new-null': 'warn',
 
       // RATIONALE:         See the @rushstack/eslint-plugin documentation
-      '@rushstack/prefer-ecmascript-private-fields': 'warn',
+      '@rushstack/prefer-ecmascript-private-members': 'warn',
 
       // RATIONALE:         See the @rushstack/eslint-plugin documentation
       '@rushstack/typedef-var': 'warn',

eslint/eslint-config/profile/_common.js

@@ -237,7 +237,7 @@ function buildRules(profile) {
           '@rushstack/no-new-null': 'warn',
 
           // RATIONALE:         See the @rushstack/eslint-plugin documentation
-          '@rushstack/prefer-ecmascript-private-fields': 'warn',
+          '@rushstack/prefer-ecmascript-private-members': 'warn',
 
           // RATIONALE:         See the @rushstack/eslint-plugin documentation
           '@rushstack/typedef-var': 'warn',

eslint/eslint-plugin/README.md

@@ -425,18 +425,20 @@ enum E {
 let e: E._PrivateMember = E._PrivateMember; // okay, because _PrivateMember is declared by E
 ```
 
-## `@rushstack/prefer-ecmascript-private-fields`
+## `@rushstack/prefer-ecmascript-private-members`
 
-Require ECMAScript private fields instead of fields declared with TypeScript's `private` modifier.
+Require ECMAScript private syntax for fields, methods, and accessors declared with TypeScript's `private`
+modifier.
 
 #### Rule Details
 
-ECMAScript `#` fields provide runtime privacy. TypeScript's `private` modifier is erased during compilation,
-allowing the field to be read or written through JavaScript, bracket notation, or type assertions.
+ECMAScript `#` members provide runtime privacy. TypeScript's `private` modifier is erased during compilation,
+allowing the member to be accessed through JavaScript, bracket notation, or type assertions.
 
-This rule applies only to class fields. Private methods, accessors, and constructor parameter properties are
-not affected. The rule does not provide an autofix because converting a field requires updating every reference
-and may change runtime behavior for reflection or objects created without invoking the constructor.
+This rule applies to class fields, methods, and accessors. Private constructors and constructor parameter
+properties are not affected. The rule does not provide an autofix because converting a member requires updating
+every reference and may change runtime behavior for reflection or objects created without invoking the
+constructor.
 
 #### Examples
 
@@ -445,6 +447,7 @@ The following pattern is considered a problem:
 ```ts
 class Example {
   private value: string = ''; // error
+  private calculate(): number {} // error
 }
 ```
 
@@ -453,6 +456,7 @@ The following pattern is NOT considered a problem:
 ```ts
 class Example {
   #value: string = '';
+  #calculate(): number {}
 }
 ```
 

eslint/eslint-plugin/src/index.ts

@@ -14,7 +14,7 @@ import { normalizedImportsRule } from './normalized-imports';
 import { typedefVar } from './typedef-var';
 import { importRequiresChunkNameRule } from './import-requires-chunk-name';
 import { pairReactDomRenderUnmountRule } from './pair-react-dom-render-unmount';
-import { preferEcmascriptPrivateFieldsRule } from './prefer-ecmascript-private-fields';
+import { preferEcmascriptPrivateMembersRule } from './prefer-ecmascript-private-members';
 
 interface IPlugin {
   rules: { [ruleName: string]: TSESLint.RuleModule<string, unknown[]> };
@@ -55,8 +55,8 @@ const plugin: IPlugin = {
     // Full name: "@rushstack/pair-react-dom-render-unmount"
     'pair-react-dom-render-unmount': pairReactDomRenderUnmountRule,
 
-    // Full name: "@rushstack/prefer-ecmascript-private-fields"
-    'prefer-ecmascript-private-fields': preferEcmascriptPrivateFieldsRule
+    // Full name: "@rushstack/prefer-ecmascript-private-members"
+    'prefer-ecmascript-private-members': preferEcmascriptPrivateMembersRule
   }
 };
 

…/src/prefer-ecmascript-private-fields.ts …src/prefer-ecmascript-private-members.tseslint/eslint-plugin/src/prefer-ecmascript-private-fields.ts renamed to eslint/eslint-plugin/src/prefer-ecmascript-private-members.ts eslint/eslint-plugin/src/prefer-ecmascript-private-fields.ts renamed to eslint/eslint-plugin/src/prefer-ecmascript-private-members.ts

@@ -3,20 +3,20 @@
 
 import type { TSESLint, TSESTree } from '@typescript-eslint/utils';
 
-type MessageIds = 'use-ecmascript-private-field';
+type MessageIds = 'use-ecmascript-private-member';
 type Options = [];
 
-const preferEcmascriptPrivateFieldsRule: TSESLint.RuleModule<MessageIds, Options> = {
+const preferEcmascriptPrivateMembersRule: TSESLint.RuleModule<MessageIds, Options> = {
   defaultOptions: [],
   meta: {
     type: 'suggestion',
     messages: {
-      'use-ecmascript-private-field':
-        'Use an ECMAScript private field ("#field") instead of the TypeScript "private" modifier.'
+      'use-ecmascript-private-member':
+        'Use ECMAScript private syntax ("#member") instead of the TypeScript "private" modifier.'
     },
     schema: [],
     docs: {
-      description: 'Require ECMAScript private fields instead of TypeScript private class fields',
+      description: 'Require ECMAScript private syntax for private class fields, methods, and accessors',
       recommended: 'recommended',
       url: 'https://www.npmjs.com/package/@rushstack/eslint-plugin'
     } as TSESLint.RuleMetaDataDocs
@@ -26,11 +26,19 @@ const preferEcmascriptPrivateFieldsRule: TSESLint.RuleModule<MessageIds, Options
       if (node.accessibility === 'private') {
         context.report({
           node,
-          messageId: 'use-ecmascript-private-field'
+          messageId: 'use-ecmascript-private-member'
+        });
+      }
+    },
+    MethodDefinition(node: TSESTree.MethodDefinition): void {
+      if (node.accessibility === 'private' && node.kind !== 'constructor') {
+        context.report({
+          node,
+          messageId: 'use-ecmascript-private-member'
         });
       }
     }
   })
 };
 
-export { preferEcmascriptPrivateFieldsRule };
+export { preferEcmascriptPrivateMembersRule };

…prefer-ecmascript-private-fields.test.ts …refer-ecmascript-private-members.test.tseslint/eslint-plugin/src/test/prefer-ecmascript-private-fields.test.ts renamed to eslint/eslint-plugin/src/test/prefer-ecmascript-private-members.test.ts eslint/eslint-plugin/src/test/prefer-ecmascript-private-fields.test.ts renamed to eslint/eslint-plugin/src/test/prefer-ecmascript-private-members.test.ts

@@ -3,53 +3,78 @@
 
 import type { RuleTester } from '@typescript-eslint/rule-tester';
 
-import { preferEcmascriptPrivateFieldsRule } from '../prefer-ecmascript-private-fields';
+import { preferEcmascriptPrivateMembersRule } from '../prefer-ecmascript-private-members';
 import { getRuleTesterWithoutProject } from './ruleTester';
 
 const ruleTester: RuleTester = getRuleTesterWithoutProject();
 
-ruleTester.run('prefer-ecmascript-private-fields', preferEcmascriptPrivateFieldsRule, {
+ruleTester.run('prefer-ecmascript-private-members', preferEcmascriptPrivateMembersRule, {
   invalid: [
     {
       code: 'class Example { private value: string = ""; }',
-      errors: [{ messageId: 'use-ecmascript-private-field' }]
+      errors: [{ messageId: 'use-ecmascript-private-member' }]
     },
     {
       code: 'class Example { private static readonly values: Set<string> = new Set(); }',
-      errors: [{ messageId: 'use-ecmascript-private-field' }]
+      errors: [{ messageId: 'use-ecmascript-private-member' }]
     },
     {
       code: 'class Example { private optional?: string; private assigned!: string; }',
       errors: [
-        { messageId: 'use-ecmascript-private-field' },
-        { messageId: 'use-ecmascript-private-field' }
+        { messageId: 'use-ecmascript-private-member' },
+        { messageId: 'use-ecmascript-private-member' }
       ]
     },
     {
       code: 'class Example { declare private value: string; }',
-      errors: [{ messageId: 'use-ecmascript-private-field' }]
+      errors: [{ messageId: 'use-ecmascript-private-member' }]
     },
     {
       code: 'class Example { private ["value"]: string = ""; }',
-      errors: [{ messageId: 'use-ecmascript-private-field' }]
+      errors: [{ messageId: 'use-ecmascript-private-member' }]
+    },
+    {
+      code: 'class Example { private calculate(): number { return 1; } }',
+      errors: [{ messageId: 'use-ecmascript-private-member' }]
+    },
+    {
+      code: [
+        'class Example {',
+        '  private get value(): string { return ""; }',
+        '  private set value(value: string) {}',
+        '}'
+      ].join('\n'),
+      errors: [
+        { messageId: 'use-ecmascript-private-member' },
+        { messageId: 'use-ecmascript-private-member' }
+      ]
     }
   ],
   valid: [
     {
       code: 'class Example { #value: string = ""; static #values: Set<string> = new Set(); }'
     },
+    {
+      code: [
+        'class Example {',
+        '  #calculate(): number { return 1; }',
+        '  get #value(): string { return ""; }',
+        '  set #value(value: string) {}',
+        '}'
+      ].join('\n')
+    },
     {
       code: 'class Example { public value: string = ""; protected otherValue: string = ""; }'
     },
     {
       code: [
         'class Example {',
-        '  private method(): void {}',
-        '  private get value(): string { return ""; }',
-        '  private set value(value: string) {}',
         '  public constructor(private readonly parameter: string) {}',
         '}'
       ].join('\n')
+    },
+    {
+      code: 'class Example { private constructor() {} }'
     }
   ]
 });