fix: persist formatting of source map JSON

Author: IchordeDionysos

.idea/copilotDiffState.xml

@@ -85,7 +85,14 @@ export function injectDebugIdIntoSourceMap(json: string, id: string): string {
     return json;
   }
 
+  if (parsed['debugId'] === id) {
+    return json;
+  }
+
   parsed['debugId'] = id;
 
-  return JSON.stringify(parsed);
+  // Preserve existing pretty-print indentation when the source map is formatted.
+  const indent = json.match(/^[^{]*{\r?\n([ \t]+)/)?.[1];
+
+  return JSON.stringify(parsed, null, indent);
 }

packages/angular/build/src/utils/debug-id.ts

@@ -82,6 +82,18 @@ describe('debug-id', () => {
       expect(updated.debugId).toBe(id);
     });
 
+    it('returns the original input when debugId already matches', () => {
+      const map = '{\n  "version": 3,\n  "debugId": "11111111-2222-5333-9444-555555555555",\n  "mappings": ""\n}';
+      expect(injectDebugIdIntoSourceMap(map, id)).toBe(map);
+    });
+
+    it('preserves indentation when updating a pretty-printed source map', () => {
+      const map = '{\n\t"version": 3,\n\t"mappings": ""\n}';
+      expect(injectDebugIdIntoSourceMap(map, id)).toBe(
+        '{\n\t"version": 3,\n\t"mappings": "",\n\t"debugId": "11111111-2222-5333-9444-555555555555"\n}',
+      );
+    });
+
     it('returns the original input when JSON is malformed', () => {
       const malformed = '{ this is not json';
       expect(injectDebugIdIntoSourceMap(malformed, id)).toBe(malformed);