[EC-648] Fix esm features in node testing environment (#4223)

* Add AST transformer to remove import.meta in tests

apps/web/src/app/app.module.ts

@@ -6,7 +6,7 @@ import { BrowserAnimationsModule } from "@angular/platform-browser/animations";
 import { InfiniteScrollModule } from "ngx-infinite-scroll";
 
 import { AppComponent } from "./app.component";
-import { CoreModule } from "./core/core.module";
+import { CoreModule } from "./core";
 import { OssRoutingModule } from "./oss-routing.module";
 import { OssModule } from "./oss.module";
 import { WildcardRoutingModule } from "./wildcard-routing.module";

apps/web/src/app/core/index.ts

@@ -1,7 +1,4 @@
-// Do not export this here or it will import MultithreadEncryptService (via JslibServicesModule) into test code.
+export * from "./core.module";
-// MultithreadEncryptService contains ES2020 features (import.meta) which are not supported in Node and Jest.
-// Revisit this when Node & Jest get stable support for ESM.
-// export * from "./core.module";
 export * from "./event.service";
 export * from "./policy-list.service";
 export * from "./router.service";

bitwarden_license/bit-web/src/app/app.module.ts

@@ -7,7 +7,7 @@ import { RouterModule } from "@angular/router";
 import { InfiniteScrollModule } from "ngx-infinite-scroll";
 
 import { JslibModule } from "@bitwarden/angular/jslib.module";
-import { CoreModule } from "@bitwarden/web-vault/app/core/core.module";
+import { CoreModule } from "@bitwarden/web-vault/app/core";
 import { OssRoutingModule } from "@bitwarden/web-vault/app/oss-routing.module";
 import { OssModule } from "@bitwarden/web-vault/app/oss.module";
 import { WildcardRoutingModule } from "@bitwarden/web-vault/app/wildcard-routing.module";

libs/shared/es2020-transformer.ts

@@ -0,0 +1,36 @@
+import * as ts from "typescript";
+
+// Custom Typescript AST transformer for use with ts-jest / jest-preset-angular
+// Removes specified ES2020 syntax from source code, as node does not support it yet
+// Reference: https://kulshekhar.github.io/ts-jest/docs/getting-started/options/astTransformers
+// Use this tool to understand how we identify and filter AST nodes: https://ts-ast-viewer.com/
+
+/**
+ * Remember to increase the version whenever transformer's content is changed. This is to inform Jest to not reuse
+ * the previous cache which contains old transformer's content
+ */
+export const version = 1;
+export const name = "bit-es2020-transformer";
+
+// Returns true for 'import.meta' statements
+const isImportMetaStatement = (node: ts.Node) =>
+  ts.isPropertyAccessExpression(node) &&
+  ts.isMetaProperty(node.expression) &&
+  node.expression.keywordToken === ts.SyntaxKind.ImportKeyword;
+
+export const factory = function (/*opts?: Opts*/) {
+  function visitor(ctx: ts.TransformationContext, sf: ts.SourceFile) {
+    const visitor: ts.Visitor = (node: ts.Node): ts.VisitResult<any> => {
+      if (isImportMetaStatement(node)) {
+        return null;
+      }
+
+      // Continue searching child nodes
+      return ts.visitEachChild(node, visitor, ctx);
+    };
+    return visitor;
+  }
+  return (ctx: ts.TransformationContext): ts.Transformer<any> => {
+    return (sf: ts.SourceFile) => ts.visitNode(sf, visitor(ctx, sf));
+  };
+};

libs/shared/jest.config.base.js

@@ -19,6 +19,9 @@ module.exports = {
       // 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,
+      astTransformers: {
+        before: ["<rootDir>/../../libs/shared/es2020-transformer.ts"],
+      },
     },
   },
 };