private async resolveModule()

in packages/jest-runtime/src/index.ts [531:666]
93 lines of code
18 McCabe index (conditional complexity)

  private async resolveModule<T = unknown>(
    specifier: string,
    referencingIdentifier: string,
    context: VMContext,
  ): Promise<T> {
    if (this.isTornDown) {
      this._logFormattedReferenceError(
        'You are trying to `import` a file after the Jest environment has been torn down.',
      );
      process.exitCode = 1;
      // @ts-expect-error - exiting
      return;
    }

    if (specifier === '@jest/globals') {
      const fromCache = this._esmoduleRegistry.get('@jest/globals');

      if (fromCache) {
        return fromCache;
      }
      const globals = this.getGlobalsForEsm(referencingIdentifier, context);
      this._esmoduleRegistry.set('@jest/globals', globals);

      return globals;
    }

    if (specifier.startsWith('data:')) {
      if (
        await this._shouldMockModule(
          referencingIdentifier,
          specifier,
          this._explicitShouldMockModule,
          {conditions: this.esmConditions},
        )
      ) {
        return this.importMock(referencingIdentifier, specifier, context);
      }

      const fromCache = this._esmoduleRegistry.get(specifier);

      if (fromCache) {
        return fromCache;
      }

      const match = specifier.match(dataURIRegex);

      if (!match || !match.groups) {
        throw new Error('Invalid data URI');
      }

      const mime = match.groups.mime;
      if (mime === 'application/wasm') {
        throw new Error('WASM is currently not supported');
      }

      const encoding = match.groups.encoding;
      let code = match.groups.code;
      if (!encoding || encoding === 'charset=utf-8') {
        code = decodeURIComponent(code);
      } else if (encoding === 'base64') {
        code = Buffer.from(code, 'base64').toString();
      } else {
        throw new Error(`Invalid data URI encoding: ${encoding}`);
      }

      let module;
      if (mime === 'application/json') {
        module = new SyntheticModule(
          ['default'],
          function () {
            const obj = JSON.parse(code);
            // @ts-expect-error: TS doesn't know what `this` is
            this.setExport('default', obj);
          },
          {context, identifier: specifier},
        );
      } else {
        module = new SourceTextModule(code, {
          context,
          identifier: specifier,
          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,
            );

            return this.linkAndEvaluateModule(module);
          },
          initializeImportMeta(meta: ImportMeta) {
            meta.url = specifier;
          },
        });
      }

      this._esmoduleRegistry.set(specifier, module);
      return module;
    }

    if (specifier.startsWith('file://')) {
      specifier = fileURLToPath(specifier);
    }

    const [path, query] = specifier.split('?');

    if (
      await this._shouldMockModule(
        referencingIdentifier,
        path,
        this._explicitShouldMockModule,
        {conditions: this.esmConditions},
      )
    ) {
      return this.importMock(referencingIdentifier, path, context);
    }

    const resolved = await this._resolveModule(referencingIdentifier, path, {
      conditions: this.esmConditions,
    });

    if (
      this._resolver.isCoreModule(resolved) ||
      this.unstable_shouldLoadAsEsm(resolved)
    ) {
      return this.loadEsmModule(resolved, query);
    }

    return this.loadCjsAsEsm(referencingIdentifier, resolved, context);
  }