Keep themed component registry up to date

When the ESLint runs in an IDE service, registries used to remain fixed and rules could not respond to changes (e.g. if a new component is made themeable) until the IDE is restarted.
This commit introduces a file watcher to register/unregister components on the fly.

lint/src/util/theme-support.ts

@@ -7,6 +7,7 @@
  */
 
 import { TSESTree } from '@typescript-eslint/utils';
+import chokidar from 'chokidar';
 import { readFileSync } from 'fs';
 import { basename } from 'path';
 import ts, { Identifier } from 'typescript';
@@ -87,7 +88,7 @@ class ThemeableComponentRegistry {
     this.byWrapperPath = new Map();
   }
 
-  public initialize(prefix = '') {
+  public initialize(prefix = '', watch = true) {
     if (this.entries.size > 0) {
       return;
     }
@@ -148,6 +149,20 @@ class ThemeableComponentRegistry {
       traverse(source);
     }
 
+    function unregisterWrapper(path: string) {
+      const entry = themeableComponents.byWrapperPath.get(path);
+
+      if (entry === undefined) {
+        return;
+      }
+
+      themeableComponents.entries.delete(entry);
+      themeableComponents.byWrapperPath.delete(entry.wrapperPath);
+      themeableComponents.byWrapperClass.delete(entry.wrapperClass);
+      themeableComponents.byBasePath.delete(entry.basePath);
+      themeableComponents.byBaseClass.delete(entry.baseClass);
+    }
+
     const glob = require('glob');
 
     // note: this outputs Unix-style paths on Windows
@@ -156,6 +171,15 @@ class ThemeableComponentRegistry {
     for (const wrapper of wrappers) {
       registerWrapper(wrapper);
     }
+
+    // Continue watching files for changes
+    if (watch) {
+      chokidar
+        .watch(prefix + 'src/app/**/themed-*.component.ts')
+        .on('add', registerWrapper)
+        .on('change', registerWrapper)
+        .on('unlink', unregisterWrapper);
+    }
   }
 
   private add(entry: ThemeableComponentRegistryEntry) {

lint/test/testing.ts

@@ -17,7 +17,7 @@ import {
 
 
 // Register themed components from test fixture
-themeableComponents.initialize(FIXTURE);
+themeableComponents.initialize(FIXTURE, false);
 
 TypeScriptRuleTester.itOnly = fit;
 TypeScriptRuleTester.itSkip = xit;

package.json

@@ -124,6 +124,7 @@
     "axios": "^1.7.4",
     "bootstrap": "^4.6.1",
     "cerialize": "0.1.18",
+    "chokidar": "^3.6.0",
     "cli-progress": "^3.12.0",
     "colors": "^1.4.0",
     "compression": "^1.7.4",