Add option to customize checked file extensions

README.md

@@ -2,7 +2,7 @@
 
 moxio/captainhook-eslint
 ========================
-This project is a plugin for [CaptainHook](https://github.com/captainhookphp/captainhook) to check JavaScript files 
+This project is a plugin for [CaptainHook](https://github.com/captainhookphp/captainhook) to check JavaScript files
 using [ESLint](https://eslint.org/) in a git pre-commit hook. By default all `*.js` and `*.mjs` files are checked, and
 the commit is blocked when one or more errors are found. Warnings produced by ESLint are ignored.
 
@@ -23,19 +23,19 @@ Add ESLint validation as a `pre-commit` to your `captainhook.json` configuration
         "actions": [
             {
                 "action": "\\Moxio\\CaptainHook\\ESLint\\ESLintAction"
-            }        
-        ]       
+            }
+        ]
     }
 }
 ```
 
-The action expects [ESLint](https://eslint.org/) to be installed as a local NPM package (i.e. available at 
+The action expects [ESLint](https://eslint.org/) to be installed as a local NPM package (i.e. available at
 `node_modules/.bin/eslint`). It should be [configured](https://eslint.org/docs/user-guide/configuring#configuring-eslint)
 in a way that automatically finds the appropriate configuration, e.g. as an `.eslintrc.*` file or with the `eslintConfig`
 field in `package.json`.
 
 ### Conditional usage
-If you want to perform ESLint validation only when ESLint is installed (i.e. available at `node_modules/.bin/eslint`), 
+If you want to perform ESLint validation only when ESLint is installed (i.e. available at `node_modules/.bin/eslint`),
 you can add a corresponding condition to the action:
 ```json
 {
@@ -49,15 +49,36 @@ you can add a corresponding condition to the action:
                         "exec": "\\Moxio\\CaptainHook\\ESLint\\Condition\\ESLintInstalled"
                     }
                 ]
-            }        
-        ]       
+            }
+        ]
     }
 }
 ```
-This may be useful in scenarios where you have a shared CaptainHook configuration file that is 
+This may be useful in scenarios where you have a shared CaptainHook configuration file that is
 [included](https://captainhookphp.github.io/captainhook/configure.html#includes) both in projects that use ESLint and
 projects that don't. If ESLint is installed, the action is run. In projects without ESLint, the validation is skipped.
 
+### Configuring checked file extensions
+
+By default, committed files with a `.js` or `.mjs` extension will be checked. If you want to customize this,
+e.g. to also validate TypeScript files, you can do so with the `extensions` option, which accepts an array
+with extensions of files to lint:
+```json
+{
+    "pre-commit": {
+        "enabled": true,
+        "actions": [
+            {
+                "action": "\\Moxio\\CaptainHook\\ESLint\\ESLintAction",
+				"options": {
+					"extensions": [ "js", "mjs", "ts", "tsx" ]
+				}
+            }
+        ]
+    }
+}
+```
+
 Versioning
 ----------
 This project adheres to [Semantic Versioning](http://semver.org/).

src/ESLintAction.php

@@ -10,11 +10,14 @@
 
 class ESLintAction implements Action {
     public function execute(Config $config, IO $io, Repository $repository, Config\Action $action): void {
+        $options = $action->getOptions();
+        $extensions = $options->get("extensions", ["js", "mjs"]);
+
         $index_operator = $repository->getIndexOperator();
-        $changed_js_files = array_merge(
-            $index_operator->getStagedFilesOfType("js"),
-            $index_operator->getStagedFilesOfType("mjs")
-        );
+        $changed_js_files = [];
+        foreach ($extensions as $extension) {
+            $changed_js_files = array_merge($changed_js_files, $index_operator->getStagedFilesOfType($extension));
+        }
 
         if (count($changed_js_files) === 0) {
             return;