refactor: create @docusaurus/bundler and @docusaurus/babel packages (#10511)

packages/docusaurus-bundler/src/compiler.ts

@@ -0,0 +1,87 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import {type Configuration} from 'webpack';
+import logger from '@docusaurus/logger';
+import formatWebpackMessages from 'react-dev-utils/formatWebpackMessages';
+import type webpack from 'webpack';
+import type {CurrentBundler} from '@docusaurus/types';
+
+export function formatStatsErrorMessage(
+  statsJson: ReturnType<webpack.Stats['toJson']> | undefined,
+): string | undefined {
+  if (statsJson?.errors?.length) {
+    // TODO formatWebpackMessages does not print stack-traces
+    // Also the error causal chain is lost here
+    // We log the stacktrace inside serverEntry.tsx for now (not ideal)
+    const {errors} = formatWebpackMessages(statsJson);
+    return errors
+      .map((str) => logger.red(str))
+      .join(`\n\n${logger.yellow('--------------------------')}\n\n`);
+  }
+  return undefined;
+}
+
+export function printStatsWarnings(
+  statsJson: ReturnType<webpack.Stats['toJson']> | undefined,
+): void {
+  if (statsJson?.warnings?.length) {
+    statsJson.warnings?.forEach((warning) => {
+      logger.warn(warning);
+    });
+  }
+}
+
+declare global {
+  interface Error {
+    /** @see https://webpack.js.org/api/node/#error-handling */
+    details?: unknown;
+  }
+}
+
+export function compile({
+  configs,
+  currentBundler,
+}: {
+  configs: Configuration[];
+  currentBundler: CurrentBundler;
+}): Promise<webpack.MultiStats> {
+  return new Promise((resolve, reject) => {
+    const compiler = currentBundler.instance(configs);
+    compiler.run((err, stats) => {
+      if (err) {
+        logger.error(err.stack ?? err);
+        if (err.details) {
+          logger.error(err.details);
+        }
+        reject(err);
+      }
+      // Let plugins consume all the stats
+      const errorsWarnings = stats?.toJson('errors-warnings');
+      if (stats?.hasErrors()) {
+        const statsErrorMessage = formatStatsErrorMessage(errorsWarnings);
+        reject(
+          new Error(
+            `Failed to compile due to Webpack errors.\n${statsErrorMessage}`,
+          ),
+        );
+      }
+      printStatsWarnings(errorsWarnings);
+
+      // Webpack 5 requires calling close() so that persistent caching works
+      // See https://github.com/webpack/webpack.js.org/pull/4775
+      compiler.close((errClose) => {
+        if (errClose) {
+          logger.error(`Error while closing Webpack compiler: ${errClose}`);
+          reject(errClose);
+        } else {
+          resolve(stats!);
+        }
+      });
+    });
+  });
+}