fix(linter): update allowed ESLint config file extensions (#30127)

ESLint added experimental support for typescript config files since
[9.9.0](https://eslint.org/blog/2024/08/eslint-v9.9.0-released/#experimental-typescript-configuration-files),
and as of
[9.18.0](https://eslint.org/blog/2025/01/eslint-v9.18.0-released/#stable-typescript-configuration-file-support)
that support is stable. This PR add ts/mts/cts to the list of known
eslint config files, and adds the same extensions to config file
generators

## Current Behavior
When using the eslint executor with a ts file, returns error "When using
the new Flat Config with ESLint, all configs must be named
eslint.config.js or eslint.config.cjs and .eslintrc files may not be
used. See
https://eslint.org/docs/latest/use/configure/configuration-files"

When using the eslint plugin, the inferred task is not created for
projects that do not have a non-ts eslint config.

### Workarounds
- Compiling ts rules/configs in a project. Introduces other issues
- Using jiti or comparable
- For plugin users, having a fake eslint.config.js at the root allows
the inferred task to be created. ESLint will still use the ts config.
  - Cache targets are wrong
  - Complications in non-monorepo workspaces

## Expected Behavior
When using the eslint executor with a ts file, no error is thrown.

When using the eslint plugin with a ts file, the inferred task is
created.

## Related Issue(s)
<!-- Please link the issue being fixed so it gets closed when this is
merged. -->
No issues, but addresses [this
discussion](https://github.com/nrwl/nx/discussions/29710#discussion-7856165)

---------

Co-authored-by: Leosvel Pérez Espinosa <leosvel.perez.espinosa@gmail.com>

packages/angular/src/generators/add-linting/add-linting.spec.ts

@@ -137,7 +137,7 @@ describe('addLinting generator', () => {
                       "error",
                       {
                           ignoredFiles: [
-                              "{projectRoot}/eslint.config.{js,cjs,mjs}"
+                              "{projectRoot}/eslint.config.{js,cjs,mjs,ts,cts,mts}"
                           ]
                       }
                   ]
@@ -206,7 +206,7 @@ describe('addLinting generator', () => {
                       {
                           enforceBuildableLibDependency: true,
                           allow: [
-                              "^.*/eslint(\\\\.base)?\\\\.config\\\\.[cm]?js$"
+                              "^.*/eslint(\\\\.base)?\\\\.config\\\\.[cm]?[jt]s$"
                           ],
                           depConstraints: [
                               {

packages/eslint/src/generators/init/global-eslint-config.ts

@@ -137,7 +137,7 @@ export const getGlobalFlatEslintConfiguration = (
                 allow: [
                   // This allows a root project to be present without causing lint errors
                   // since all projects will depend on this base file.
-                  '^.*/eslint(\\.base)?\\.config\\.[cm]?js$',
+                  '^.*/eslint(\\.base)?\\.config\\.[cm]?[jt]s$',
                 ],
                 depConstraints: [
                   { sourceTag: '*', onlyDependOnLibsWithTags: ['*'] },

packages/eslint/src/generators/lint-project/lint-project.spec.ts

@@ -308,7 +308,7 @@ describe('@nx/eslint:lint-project', () => {
                       {
                           enforceBuildableLibDependency: true,
                           allow: [
-                              "^.*/eslint(\\\\.base)?\\\\.config\\\\.[cm]?js$"
+                              "^.*/eslint(\\\\.base)?\\\\.config\\\\.[cm]?[jt]s$"
                           ],
                           depConstraints: [
                               {
@@ -379,7 +379,7 @@ describe('@nx/eslint:lint-project', () => {
                       {
                           enforceBuildableLibDependency: true,
                           allow: [
-                              "^.*/eslint(\\\\.base)?\\\\.config\\\\.[cm]?js$"
+                              "^.*/eslint(\\\\.base)?\\\\.config\\\\.[cm]?[jt]s$"
                           ],
                           depConstraints: [
                               {
@@ -495,7 +495,9 @@ describe('@nx/eslint:lint-project', () => {
               "@nx/dependency-checks": [
                 "error",
                 {
-                  "ignoredFiles": ["{projectRoot}/eslint.config.{js,cjs,mjs}"]
+                  "ignoredFiles": [
+                    "{projectRoot}/eslint.config.{js,cjs,mjs,ts,cts,mts}"
+                  ]
                 }
               ]
             }

packages/eslint/src/generators/lint-project/lint-project.ts

@@ -293,8 +293,10 @@ function createEsLintConfiguration(
         '@nx/dependency-checks': [
           'error',
           {
-            // With flat configs, we don't want to include imports in the eslint js/cjs/mjs files to be checked
+            // With flat configs, we don't want to include imports in the eslint js/cjs/mjs/ts/cts/mts files to be checked
-            ignoredFiles: ['{projectRoot}/eslint.config.{js,cjs,mjs}'],
+            ignoredFiles: [
+              '{projectRoot}/eslint.config.{js,cjs,mjs,ts,cts,mts}',
+            ],
           },
         ],
       },

packages/eslint/src/utils/flat-config.ts

@@ -5,13 +5,20 @@ export const eslintFlatConfigFilenames = [
   'eslint.config.cjs',
   'eslint.config.js',
   'eslint.config.mjs',
+  'eslint.config.cts',
+  'eslint.config.ts',
+  'eslint.config.mts',
 ];
 
 export const baseEslintConfigFilenames = [
   'eslint.base.js',
+  'eslint.base.ts',
   'eslint.base.config.cjs',
   'eslint.base.config.js',
   'eslint.base.config.mjs',
+  'eslint.base.config.cts',
+  'eslint.base.config.ts',
+  'eslint.base.config.mts',
 ];
 
 export function getRootESLintFlatConfigFilename(tree: Tree): string {

packages/plugin/src/generators/lint-checks/generator.spec.ts

@@ -159,7 +159,7 @@ describe('lint-checks generator', () => {
               "error",
               {
                 "ignoredFiles": [
-                  "{projectRoot}/eslint.config.{js,cjs,mjs}",
+                  "{projectRoot}/eslint.config.{js,cjs,mjs,ts,cts,mts}",
                 ],
               },
             ],

packages/vite/src/generators/configuration/configuration.spec.ts

@@ -296,7 +296,7 @@ describe('@nx/vite:configuration', () => {
             'error',
             {
               ignoredFiles: [
-                '{projectRoot}/eslint.config.{js,cjs,mjs}',
+                '{projectRoot}/eslint.config.{js,cjs,mjs,ts,cts,mts}',
                 '{projectRoot}/vite.config.{js,ts,mjs,mts}',
               ],
             },