fix(@jest/transform): do not attempt instrumenting .json modules (#…

…14048)

CHANGELOG.md

@@ -8,6 +8,7 @@
 - `[jest-environment-jsdom, jest-environment-node]` Fix assignment of `customExportConditions` via `testEnvironmentOptions` when custom env subclass defines a default value ([#13989](https://github.com/facebook/jest/pull/13989))
 - `[jest-matcher-utils]` Fix copying value of inherited getters ([#14007](https://github.com/facebook/jest/pull/14007))
 - `[jest-snapshot]` Fix a potential bug when not using prettier and improve performance ([#14036](https://github.com/facebook/jest/pull/14036))
+- `[@jest/transform]` Do not instrument `.json` modules ([#14048](https://github.com/facebook/jest/pull/14048))
 
 ### Chore & Maintenance
 

packages/jest-transform/src/__tests__/shouldInstrument.test.ts

@@ -119,6 +119,12 @@ describe('shouldInstrument', () => {
         ['dont/collect/coverage.js'],
       );
     });
+
+    it('when file is a .json module, but matches forceCoverageMatch', () => {
+      testShouldInstrument('do/collect/coverage.json', defaultOptions, {
+        forceCoverageMatch: ['**/do/**/*.json'],
+      });
+    });
   });
 
   describe('should return false', () => {
@@ -245,5 +251,13 @@ describe('shouldInstrument', () => {
         ['do/collect/coverage.js'],
       );
     });
+
+    it('when file is a .json module', () => {
+      testShouldInstrument(
+        'dont/collect/coverage.json',
+        defaultOptions,
+        defaultConfig,
+      );
+    });
   });
 });

packages/jest-transform/src/shouldInstrument.ts

@@ -114,5 +114,9 @@ export default function shouldInstrument(
     }
   }
 
+  if (filename.endsWith('.json')) {
+    return false;
+  }
+
   return true;
 }