chore(nextjs): Remove obsolete dataFetchers loader (#5713)

This removes the dataFetchers loader and its associated files and dependencies, now that it's been supplanted by the proxy loader. It also changes the build config slightly - somehow, the presence of everything this PR deletes made it so the loaders files output themselves where we want them, even without the entryFileNames setting they ought to have needed. Alas, doing the deletions broke the spell, and now they won't build to the right place without entryFileNames, so this adds it. (Even though we've now reverted to what logically should be true, I'm still baffled, because what on earth was happening before?)

Note: Until we fully settle the CJS questions, I'm leaving isESM.ts in the SDK, even though after this change it will be (for the moment) unused.

Author: lobsterkatie

packages/nextjs/package.json

@@ -17,7 +17,6 @@
     "access": "public"
   },
   "dependencies": {
-    "@babel/parser": "^7.18.10",
     "@rollup/plugin-sucrase": "4.0.4",
     "@sentry/core": "7.12.1",
     "@sentry/hub": "7.12.1",
@@ -29,14 +28,11 @@
     "@sentry/utils": "7.12.1",
     "@sentry/webpack-plugin": "1.19.0",
     "chalk": "3.0.0",
-    "jscodeshift": "^0.13.1",
     "rollup": "2.78.0",
     "tslib": "^1.9.3"
   },
   "devDependencies": {
-    "@babel/types": "7.18.10",
     "@sentry/nextjs": "7.12.1",
-    "@types/jscodeshift": "^0.11.5",
     "@types/webpack": "^4.41.31",
     "next": "10.1.3"
   },

packages/nextjs/rollup.npm.config.js

@@ -14,17 +14,12 @@ export default [
   ),
   ...makeNPMConfigVariants(
     makeBaseNPMConfig({
-      entrypoints: [
-        'src/config/templates/prefixLoaderTemplate.ts',
-        'src/config/templates/proxyLoaderTemplate.ts',
-        'src/config/templates/dataFetchersLoaderTemplate.ts',
-      ],
+      entrypoints: ['src/config/templates/prefixLoaderTemplate.ts', 'src/config/templates/proxyLoaderTemplate.ts'],
 
       packageSpecificConfig: {
         plugins: [plugins.makeRemoveMultiLineCommentsPlugin()],
         output: {
-          // Preserve the original file structure (i.e., so that everything is still relative to `src`). (Not entirely
-          // clear why this is necessary here and not for other entrypoints in this file.)
+          // Preserve the original file structure (i.e., so that everything is still relative to `src`)
           entryFileNames: 'config/templates/[name].js',
 
           // this is going to be add-on code, so it doesn't need the trappings of a full module (and in fact actively
@@ -47,6 +42,9 @@ export default [
 
       packageSpecificConfig: {
         output: {
+          // Preserve the original file structure (i.e., so that everything is still relative to `src`)
+          entryFileNames: 'config/loaders/[name].js',
+
           // make it so Rollup calms down about the fact that we're combining default and named exports
           exports: 'named',
         },

packages/nextjs/src/config/loaders/ast.ts

@@ -1,3 +1,2 @@
 export { default as prefixLoader } from './prefixLoader';
-export { default as dataFetchersLoader } from './dataFetchersLoader';
 export { default as proxyLoader } from './proxyLoader';