[EC-497] Fix memory leaks in tests (#3421)

* Add isolatedModules:true

* Add manual typechecking in CI for libs/ tests

.github/workflows/test.yml

@@ -42,7 +42,16 @@ jobs:
       - name: Install Node dependencies
         run: npm ci
 
+      # We use isolatedModules: true which disables typechecking in tests
+      # Tests in apps/ are typechecked when their app is built, so we just do it here for libs/
+      # See https://bitwarden.atlassian.net/browse/EC-497
+      - name: Run typechecking
+        run: |
+          for p in libs/**/tsconfig.spec.json; do
+            echo "Typechecking $p"
+            npx tsc --noEmit --project $p
+          done
+
       - name: Run tests
         run: |
-          export NODE_OPTIONS=--max_old_space_size=6144
           npm run test

jest.config.js

@@ -26,4 +26,13 @@ module.exports = {
   // https://github.com/facebook/jest/issues/9430#issuecomment-1149882002
   // Also anecdotally improves performance when run locally
   maxWorkers: 3,
+  globals: {
+    "ts-jest": {
+      // Further workaround for memory leak, recommended here:
+      // https://github.com/kulshekhar/ts-jest/issues/1967#issuecomment-697494014
+      // Makes tests run faster and reduces size/rate of leak, but loses typechecking on test code
+      // See https://bitwarden.atlassian.net/browse/EC-497 for more info
+      isolatedModules: true,
+    },
+  },
 };

libs/shared/jest.config.base.js

@@ -10,10 +10,15 @@ module.exports = {
   // Also anecdotally improves performance when run locally
   maxWorkers: 3,
 
-  // Jest does not use tsconfig.spec.json by default
   globals: {
     "ts-jest": {
+      // Jest does not use tsconfig.spec.json by default
       tsconfig: "<rootDir>/tsconfig.spec.json",
+      // Further workaround for memory leak, recommended here:
+      // https://github.com/kulshekhar/ts-jest/issues/1967#issuecomment-697494014
+      // Makes tests run faster and reduces size/rate of leak, but loses typechecking on test code
+      // See https://bitwarden.atlassian.net/browse/EC-497 for more info
+      isolatedModules: true,
     },
   },
 };