feat: add support for import assertions

jestjs · Jan 24, 2023 · fe477fa · fe477fa
1 parent e0b1249
commit fe477fa
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Showing 2 changed files with 82 additions and 38 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -19,7 +19,8 @@
 - `[jest-mock]` fix mockReset and resetAllMocks undefined return ([#13692](https://github.com/facebook/jest/pull/13692))
 - `[jest-resolve]` Add global paths to `require.resolve.paths` ([#13633](https://github.com/facebook/jest/pull/13633))
 - `[jest-runtime]` Support Wasm files that import JS resources ([#13608](https://github.com/facebook/jest/pull/13608))
-- `[jest-runtime]` Using the scriptTransformer cache in jest-runner ([#13735](https://github.com/facebook/jest/pull/13735))
+- `[jest-runtime]` Using the scriptTransformer cache in `jest-runner` ([#13735](https://github.com/facebook/jest/pull/13735))
+- `[jest-runtime]` Enforce import assertions when importing JSON in ESM ([#12755](https://github.com/facebook/jest/pull/12755))
 - `[jest-snapshot]` Make sure to import `babel` outside of the sandbox ([#13694](https://github.com/facebook/jest/pull/13694))
 - `[jest-transform]` Ensure the correct configuration is passed to preprocessors specified multiple times in the `transform` option ([#13770](https://github.com/facebook/jest/pull/13770))
 

diff --git a/packages/jest-runtime/src/index.ts b/packages/jest-runtime/src/index.ts
@@ -413,7 +413,19 @@ export default class Runtime {
   private async loadEsmModule(
     modulePath: string,
     query = '',
+    importAssertions: ImportAssertions = {},
   ): Promise<VMModule> {
+    if (modulePath.endsWith('.json') && importAssertions.type !== 'json') {
+      const error: NodeJS.ErrnoException = new Error(
+        `Module "${
+          modulePath + (query ? `?${query}` : '')
+        }" needs an import assertion of type "json"`,
+      );
+      error.code = 'ERR_IMPORT_ASSERTION_TYPE_MISSING';
+
+      throw error;
+    }
+
     const cacheKey = modulePath + query;
 
     if (this._fileTransformsMutex.has(cacheKey)) {
@@ -477,39 +489,54 @@ export default class Runtime {
       });
 
       try {
-        const module = new SourceTextModule(transformedCode, {
-          context,
-          identifier: modulePath,
-          importModuleDynamically: async (
-            specifier: string,
-            referencingModule: VMModule,
-          ) => {
-            invariant(
-              runtimeSupportsVmModules,
-              'You need to run with a version of node that supports ES Modules in the VM API. See https://jestjs.io/docs/ecmascript-modules',
-            );
-            const module = await this.resolveModule(
-              specifier,
-              referencingModule.identifier,
-              referencingModule.context,
-            );
+        let module;
+        if (modulePath.endsWith('.json')) {
+          module = new SyntheticModule(
+            ['default'],
+            function () {
+              const obj = JSON.parse(transformedCode);
+              // @ts-expect-error: TS doesn't know what `this` is
+              this.setExport('default', obj);
+            },
+            {context, identifier: modulePath},
+          );
+        } else {
+          module = new SourceTextModule(transformedCode, {
+            context,
+            identifier: modulePath,
+            importModuleDynamically: async (
+              specifier: string,
+              referencingModule: VMModule,
+              importAssertions?: ImportAssertions,
+            ) => {
+              invariant(
+                runtimeSupportsVmModules,
+                'You need to run with a version of node that supports ES Modules in the VM API. See https://jestjs.io/docs/ecmascript-modules',
+              );
+              const module = await this.resolveModule(
+                specifier,
+                referencingModule.identifier,
+                referencingModule.context,
+                importAssertions,
+              );
 
-            return this.linkAndEvaluateModule(module);
-          },
-          initializeImportMeta: (meta: JestImportMeta) => {
-            meta.url = pathToFileURL(modulePath).href;
+              return this.linkAndEvaluateModule(module);
+            },
+            initializeImportMeta: (meta: JestImportMeta) => {
+              meta.url = pathToFileURL(modulePath).href;
 
-            let jest = this.jestObjectCaches.get(modulePath);
+              let jest = this.jestObjectCaches.get(modulePath);
 
-            if (!jest) {
-              jest = this._createJestObjectFor(modulePath);
+              if (!jest) {
+                jest = this._createJestObjectFor(modulePath);
 
-              this.jestObjectCaches.set(modulePath, jest);
-            }
+                this.jestObjectCaches.set(modulePath, jest);
+              }
 
-            meta.jest = jest;
-          },
-        });
+              meta.jest = jest;
+            },
+          });
+        }
 
         invariant(
           !this._esmoduleRegistry.has(cacheKey),
@@ -539,6 +566,7 @@ export default class Runtime {
     specifier: string,
     referencingIdentifier: string,
     context: VMContext,
+    importAssertions: ImportAssertions = {},
   ): Promise<T> {
     if (this.isTornDown) {
       this._logFormattedReferenceError(
@@ -627,6 +655,7 @@ export default class Runtime {
             importModuleDynamically: async (
               specifier: string,
               referencingModule: VMModule,
+              importAssertions?: ImportAssertions,
             ) => {
               invariant(
                 runtimeSupportsVmModules,
@@ -636,6 +665,7 @@ export default class Runtime {
                 specifier,
                 referencingModule.identifier,
                 referencingModule.context,
+                importAssertions,
               );
 
               return this.linkAndEvaluateModule(module);
@@ -672,9 +702,11 @@ export default class Runtime {
 
     if (
       this._resolver.isCoreModule(resolved) ||
-      this.unstable_shouldLoadAsEsm(resolved)
+      this.unstable_shouldLoadAsEsm(resolved) ||
+      // json files are modules when imported in modules
+      resolved.endsWith('.json')
     ) {
-      return this.loadEsmModule(resolved, query);
+      return this.loadEsmModule(resolved, query, importAssertions);
     }
 
     return this.loadCjsAsEsm(referencingIdentifier, resolved, context);
@@ -696,12 +728,18 @@ export default class Runtime {
       // this method can await it
       this._esmModuleLinkingMap.set(
         module,
-        module.link((specifier: string, referencingModule: VMModule) =>
-          this.resolveModule(
-            specifier,
-            referencingModule.identifier,
-            referencingModule.context,
-          ),
+        module.link(
+          (
+            specifier: string,
+            referencingModule: VMModule,
+            importCallOptions?: ImportCallOptions,
+          ) =>
+            this.resolveModule(
+              specifier,
+              referencingModule.identifier,
+              referencingModule.context,
+              importCallOptions?.assert,
+            ),
         ),
       );
     }
@@ -1628,7 +1666,11 @@ export default class Runtime {
         displayErrors: true,
         filename: scriptFilename,
         // @ts-expect-error: Experimental ESM API
-        importModuleDynamically: async (specifier: string) => {
+        importModuleDynamically: async (
+          specifier: string,
+          _script: Script,
+          importAssertions?: ImportAssertions,
+        ) => {
           invariant(
             runtimeSupportsVmModules,
             'You need to run with a version of node that supports ES Modules in the VM API. See https://jestjs.io/docs/ecmascript-modules',
@@ -1642,6 +1684,7 @@ export default class Runtime {
             specifier,
             scriptFilename,
             context,
+            importAssertions,
           );
 
           return this.linkAndEvaluateModule(module);