feat(nextjs): Remove transpileClientSDK (#11978)

I dropped the ball on this a bit to deprecate but removing it now should
still be fine.

MIGRATION.md

@@ -866,6 +866,12 @@ in order to inject the `sentry.(server|edge).config.ts` files into the server-si
 possible in the future, we are doing ourselves a favor and doing things the way Next.js intends us to do them -
 hopefully reducing bugs and jank.
 
+#### Removal of `transpileClientSDK`
+
+Since we are dropping support for Internet Explorer 11 and other other older browser versions, we are also removing the
+`transpileClientSDK` option from the Next.js SDK. If you need to support these browser versions, please configure
+Webpack and Next.js to down-compile the SDK.
+
 ### Astro SDK
 
 - [Removal of `trackHeaders` option for Astro middleware](./MIGRATION.md#removal-of-trackheaders-option-for-astro-middleware)

packages/nextjs/src/config/types.ts

@@ -334,12 +334,6 @@ export type SentryBuildOptions = {
    */
   hideSourceMaps?: boolean;
 
-  /**
-   * Instructs webpack to apply the same transpilation rules to the SDK code as apply to user code. Helpful when
-   * targeting older browsers which don't support ES6 (or ES6+ features like object spread).
-   */
-  transpileClientSDK?: boolean;
-
   /**
    * Include Next.js-internal code and code from dependencies when uploading source maps.
    *

packages/nextjs/src/config/webpack.ts

@@ -20,7 +20,6 @@ import type {
   WebpackConfigObject,
   WebpackConfigObjectWithModuleRules,
   WebpackEntryProperty,
-  WebpackModuleRule,
 } from './types';
 import { getWebpackPluginOptions } from './webpackPluginOptions';
 
@@ -305,35 +304,6 @@ export function constructWebpackConfigFunction(
       }
     }
 
-    // TODO(v8): Remove this logic since we are deprecating es5.
-    // The SDK uses syntax (ES6 and ES6+ features like object spread) which isn't supported by older browsers. For users
-    // who want to support such browsers, `transpileClientSDK` allows them to force the SDK code to go through the same
-    // transpilation that their code goes through. We don't turn this on by default because it increases bundle size
-    // fairly massively.
-    if (!isServer && userSentryOptions?.transpileClientSDK) {
-      // Find all loaders which apply transpilation to user code
-      const transpilationRules = findTranspilationRules(newConfig.module?.rules, projectDir);
-
-      // For each matching rule, wrap its `exclude` function so that it won't exclude SDK files, even though they're in
-      // `node_modules` (which is otherwise excluded)
-      transpilationRules.forEach(rule => {
-        // All matching rules will necessarily have an `exclude` property, but this keeps TS happy
-        if (rule.exclude && typeof rule.exclude === 'function') {
-          const origExclude = rule.exclude;
-
-          const newExclude = (filepath: string): boolean => {
-            if (filepath.includes('@sentry')) {
-              // `false` in this case means "don't exclude it"
-              return false;
-            }
-            return origExclude(filepath);
-          };
-
-          rule.exclude = newExclude;
-        }
-      });
-    }
-
     if (!isServer) {
       // Tell webpack to inject the client config files (containing the client-side `Sentry.init()` call) into the appropriate output
       // bundles. Store a separate reference to the original `entry` value to avoid an infinite loop. (If we don't do
@@ -385,72 +355,6 @@ export function constructWebpackConfigFunction(
   };
 }
 
-/**
- * Determine if this `module.rules` entry is one which will transpile user code
- *
- * @param rule The rule to check
- * @param projectDir The path to the user's project directory
- * @returns True if the rule transpiles user code, and false otherwise
- */
-function isMatchingRule(rule: WebpackModuleRule, projectDir: string): boolean {
-  // We want to run our SDK code through the same transformations the user's code will go through, so we test against a
-  // sample user code path
-  const samplePagePath = path.resolve(projectDir, 'pageFile.js');
-  if (rule.test && rule.test instanceof RegExp && !rule.test.test(samplePagePath)) {
-    return false;
-  }
-  if (Array.isArray(rule.include) && !rule.include.includes(projectDir)) {
-    return false;
-  }
-
-  // `rule.use` can be an object or an array of objects. For simplicity, force it to be an array.
-  const useEntries = arrayify(rule.use);
-
-  // Depending on the version of nextjs we're talking about, the loader which does the transpiling is either
-  //
-  //   'next-babel-loader' (next 10),
-  //   '/abs/path/to/node_modules/next/more/path/babel/even/more/path/loader/yet/more/path/index.js' (next 11), or
-  //   'next-swc-loader' (next 12).
-  //
-  // The next 11 option is ugly, but thankfully 'next', 'babel', and 'loader' do appear in it in the same order as in
-  // 'next-babel-loader', so we can use the same regex to test for both.
-  if (!useEntries.some(entry => entry?.loader && /next.*(babel|swc).*loader/.test(entry.loader))) {
-    return false;
-  }
-
-  return true;
-}
-
-/**
- * Find all rules in `module.rules` which transpile user code.
- *
- * @param rules The `module.rules` value
- * @param projectDir The path to the user's project directory
- * @returns An array of matching rules
- */
-function findTranspilationRules(rules: WebpackModuleRule[] | undefined, projectDir: string): WebpackModuleRule[] {
-  if (!rules) {
-    return [];
-  }
-
-  const matchingRules: WebpackModuleRule[] = [];
-
-  // Each entry in `module.rules` is either a rule in and of itself or an object with a `oneOf` property, whose value is
-  // an array of rules
-  rules.forEach(rule => {
-    // if (rule.oneOf) {
-    if (isMatchingRule(rule, projectDir)) {
-      matchingRules.push(rule);
-    } else if (rule.oneOf) {
-      const matchingOneOfRules = rule.oneOf.filter(oneOfRule => isMatchingRule(oneOfRule, projectDir));
-      matchingRules.push(...matchingOneOfRules);
-      // } else if (isMatchingRule(rule, projectDir)) {
-    }
-  });
-
-  return matchingRules;
-}
-
 /**
  * Modify the webpack `entry` property so that the code in `sentry.client.config.js` is
  * included in the the necessary bundles.