feat(bazel): remove unused ESM2022 from APF (angular#57559)

We have removed the `esm2022` directory from the generated package, as it was unused and contributed 7.7 MB to `@angular/core`. The `ng_package` rule still passes `esm2022` to the packager to perform `analyzeFileAndEnsureNoCrossImports`. A moment of reflection: You've always been there, full of potential, yet never called upon. Now, we bid you farewell. PR Close angular#57559

Author: alan-agius4

adev/src/content/tools/libraries/angular-package-format.md

@@ -26,21 +26,16 @@ The following example shows a simplified version of the `@angular/core` package'
 
 ```markdown
 node_modules/@angular/core
-├── README.md 
-├── package.json 
-├── index.d.ts 
-├── esm2022 
-│ ├── core.mjs
-│ ├── index.mjs
-│ ├── public_api.mjs
-│ └── testing 
-├── fesm2022 
+├── README.md
+├── package.json
+├── index.d.ts
+├── fesm2022
 │ ├── core.mjs
 │ ├── core.mjs.map
 │ ├── testing.mjs
 │ └── testing.mjs.map
-└── testing 
- └── index.d.ts 
+└── testing
+ └── index.d.ts
 ```
 
 This table describes the file layout under `node_modules/@angular/core` annotated to describe the purpose of files and directories:
@@ -50,8 +45,6 @@ This table describes the file layout under `node_modules/@angular/core` annotate
 | `README.md` | Package README, used by npmjs web UI. |
 | `package.json` | Primary `package.json`, describing the package itself as well as all available entrypoints and code formats. This file contains the "exports" mapping used by runtimes and tools to perform module resolution. |
 | `index.d.ts` | Bundled `.d.ts` for the primary entrypoint `@angular/core`. |
-| `esm2022/` <br /> &nbsp;&nbsp;─ `core.mjs` <br /> &nbsp;&nbsp;─ `index.mjs` <br /> &nbsp;&nbsp;─ `public_api.mjs` | Tree of `@angular/core` sources in unflattened ES2022 format. |
-| `esm2022/testing/` | Tree of the `@angular/core/testing` entrypoint in unflattened ES2022 format. |
 | `fesm2022/` <br /> &nbsp;&nbsp;─ `core.mjs` <br /> &nbsp;&nbsp;─ `core.mjs.map` <br /> &nbsp;&nbsp;─ `testing.mjs` <br /> &nbsp;&nbsp;─ `testing.mjs.map` | Code for all entrypoints in flattened \(FESM\) ES2022 format, along with source maps. |
 | `testing/` | Directory representing the "testing" entrypoint. |
 | `testing/index.d.ts` | Bundled `.d.ts` for the `@angular/core/testing` entrypoint. |
@@ -96,14 +89,10 @@ The `"exports"` field has the following structure:
  },
  ".": {
  "types": "./core.d.ts",
- "esm": "./esm2022/core.mjs",
- "esm2022": "./esm2022/core.mjs",
  "default": "./fesm2022/core.mjs"
  },
  "./testing": {
  "types": "./testing/testing.d.ts",
- "esm": "./esm2022/testing/testing.mjs",
- "esm2022": "./esm2022/testing/testing.mjs",
  "default": "./fesm2022/testing.mjs"
  }
 }
@@ -116,8 +105,6 @@ For each entrypoint, the available formats are:
 | Formats | Details |
 |:--- |:--- |
 | Typings \(`.d.ts` files\) | `.d.ts` files are used by TypeScript when depending on a given package. |
-| `es2022` | ES2022 code flattened into a single source file. |
-| `esm2022` | ES2022 code in unflattened source files \(this format is included for experimentation - see [this discussion of defaults](#note-about-the-defaults-in-packagejson) for details\). |
 | `default` | ES2022 code flattened into a single source.
 
 Tooling that is aware of these keys may preferentially select a desirable code format from `"exports"`.
@@ -263,14 +250,6 @@ To generate a flattened ES Module index file, use the following configuration op
 
 Once the index file \(for example, `my-ui-lib.js`\) is generated by ngc, bundlers and optimizers like Rollup can be used to produce the flattened ESM file.
 
-#### Note about the defaults in package.json
-
-As of webpack v4, the flattening of ES modules optimization should not be necessary for webpack users. It should be possible to get better code-splitting without flattening of modules in webpack.
-In practice, size regressions can still be seen when using unflattened modules as input for webpack v4.
-This is why `module` and `es2022` package.json entries still point to FESM files.
-This issue is being investigated. It is expected to switch the `module` and `es2022` package.json entry points to unflattened files after the size regression issue is resolved.
-The APF currently includes unflattened ESM2022 code for the purpose of validating such a future change.
-
 ### "sideEffects" flag
 
 By default, EcmaScript Modules are side-effectful: importing from a module ensures that any code at the top level of that module should run.

packages/bazel/src/ng_package/packager.ts

@@ -16,7 +16,7 @@ import {analyzeFileAndEnsureNoCrossImports} from './cross_entry_points_imports';
  * List of known `package.json` fields which provide information about
  * supported package formats and their associated entry paths.
  */
-const knownFormatPackageJsonFormatFields = ['main', 'esm2022', 'esm', 'typings', 'module'] as const;
+const knownFormatPackageJsonFormatFields = ['main', 'typings', 'module'] as const;
 
 /** Union type matching known `package.json` format fields. */
 type KnownPackageJsonFormatFields = (typeof knownFormatPackageJsonFormatFields)[number];
@@ -27,8 +27,6 @@ type KnownPackageJsonFormatFields = (typeof knownFormatPackageJsonFormatFields)[
  */
 type ConditionalExport = {
  types?: string;
- esm2022?: string;
- esm?: string;
  default?: string;
 };
 
@@ -130,16 +128,6 @@ function main(args: string[]): void {
  return path.relative(owningPackageName, file.shortPath);
  }
 
- /** Writes an ESM file into the `esm2022` output directory. */
- function writeEsm2022File(file: BazelFileInfo) {
- // Note: files which do not belong to the owning package of this `ng_package` are omitted.
- // this prevents us from accidentally bringing in transitive node module dependencies.
- const packageRelativePath = getOwningPackageRelativePath(file);
- if (!packageRelativePath.startsWith('..')) {
- copyFile(file.path, getEsm2022OutputRelativePath(file));
- }
- }
-
  /** Gets the output-relative path where the given flat ESM file should be written to. */
  function getFlatEsmOutputRelativePath(file: BazelFileInfo) {
  // Flat ESM files should be put into their owning package relative sub-path. e.g. if
@@ -150,13 +138,6 @@ function main(args: string[]): void {
  return getOwningPackageRelativePath(file);
  }
 
- /** Gets the output-relative path where a non-flat ESM2022 file should be written to. */
- function getEsm2022OutputRelativePath(file: BazelFileInfo) {
- // Path computed relative to the current package in bazel-bin. e.g. a ES2022 output file
- // in `bazel-out/<..>/packages/core/src/di.mjs` should be stored in `esm2022/src/di.mjs`.
- return path.join('esm2022', getOwningPackageRelativePath(file));
- }
-
  /** Gets the output-relative path where the typing file is being written to. */
  function getTypingOutputRelativePath(file: BazelFileInfo) {
  // Type definitions are intended to be copied into the package output while preserving the
@@ -184,12 +165,9 @@ function main(args: string[]): void {
  return getEntryPointSubpath(moduleName) !== '';
  }
 
- const crossEntryPointFailures: string[] = [];
-
- esm2022.forEach((file) => {
- crossEntryPointFailures.push(...analyzeFileAndEnsureNoCrossImports(file, metadata));
- writeEsm2022File(file);
- });
+ const crossEntryPointFailures = esm2022.flatMap((file) =>
+ analyzeFileAndEnsureNoCrossImports(file, metadata),
+ );
 
  if (crossEntryPointFailures.length) {
  console.error(crossEntryPointFailures);
@@ -342,7 +320,6 @@ function main(args: string[]): void {
  const subpath = isSecondaryEntryPoint(moduleName)
  ? `./${getEntryPointSubpath(moduleName)}`
  : '.';
- const esmIndexOutRelativePath = getEsm2022OutputRelativePath(entryPoint.index);
  const fesm2022OutRelativePath = getFlatEsmOutputRelativePath(entryPoint.fesm2022Bundle);
  const typesOutRelativePath = getTypingOutputRelativePath(entryPoint.typings);
 
@@ -351,8 +328,6 @@ function main(args: string[]): void {
  // https://github.com/microsoft/TypeScript/pull/45884.
  insertExportMappingOrError(newPackageJson, subpath, {
  types: normalizePath(typesOutRelativePath),
- esm2022: normalizePath(esmIndexOutRelativePath),
- esm: normalizePath(esmIndexOutRelativePath),
  // Note: The default conditions needs to be the last one.
  default: normalizePath(fesm2022OutRelativePath),
  });

packages/bazel/test/ng_package/common_package.spec.ts

@@ -97,32 +97,22 @@ describe('@angular/common ng_package', () => {
  './package.json': {default: './package.json'},
  '.': {
  types: './index.d.ts',
- esm2022: './esm2022/common.mjs',
- esm: './esm2022/common.mjs',
  default: './fesm2022/common.mjs',
  },
  './http': {
  types: './http/index.d.ts',
- esm2022: './esm2022/http/http.mjs',
- esm: './esm2022/http/http.mjs',
  default: './fesm2022/http.mjs',
  },
  './http/testing': {
  types: './http/testing/index.d.ts',
- esm2022: './esm2022/http/testing/testing.mjs',
- esm: './esm2022/http/testing/testing.mjs',
  default: './fesm2022/http/testing.mjs',
  },
  './testing': {
  types: './testing/index.d.ts',
- esm2022: './esm2022/testing/testing.mjs',
- esm: './esm2022/testing/testing.mjs',
  default: './fesm2022/testing.mjs',
  },
  './upgrade': {
  types: './upgrade/index.d.ts',
- esm2022: './esm2022/upgrade/upgrade.mjs',
- esm: './esm2022/upgrade/upgrade.mjs',
  default: './fesm2022/upgrade.mjs',
  },
  }),

packages/bazel/test/ng_package/core_package.spec.ts

@@ -63,32 +63,22 @@ describe('@angular/core ng_package', () => {
  './package.json': {default: './package.json'},
  '.': {
  types: './index.d.ts',
- esm2022: './esm2022/core.mjs',
- esm: './esm2022/core.mjs',
  default: './fesm2022/core.mjs',
  },
  './primitives/event-dispatch': {
  types: './primitives/event-dispatch/index.d.ts',
- esm2022: './esm2022/primitives/event-dispatch/index.mjs',
- esm: './esm2022/primitives/event-dispatch/index.mjs',
  default: './fesm2022/primitives/event-dispatch.mjs',
  },
  './primitives/signals': {
  types: './primitives/signals/index.d.ts',
- esm2022: './esm2022/primitives/signals/index.mjs',
- esm: './esm2022/primitives/signals/index.mjs',
  default: './fesm2022/primitives/signals.mjs',
  },
  './rxjs-interop': {
  types: './rxjs-interop/index.d.ts',
- esm2022: './esm2022/rxjs-interop/rxjs-interop.mjs',
- esm: './esm2022/rxjs-interop/rxjs-interop.mjs',
  default: './fesm2022/rxjs-interop.mjs',
  },
  './testing': {
  types: './testing/index.d.ts',
- esm2022: './esm2022/testing/testing.mjs',
- esm: './esm2022/testing/testing.mjs',
  default: './fesm2022/testing.mjs',
  },
  }),
@@ -140,16 +130,6 @@ describe('@angular/core ng_package', () => {
  );
  });
  });
-
- describe('esm2022', () => {
- it('should not contain any *.ngfactory.js files', () => {
- expect(shx.find('esm2022').filter((f) => f.includes('.ngfactory'))).toEqual([]);
- });
-
- it('should not contain any *.ngsummary.js files', () => {
- expect(shx.find('esm2022').filter((f) => f.includes('.ngsummary'))).toEqual([]);
- });
- });
  });
 
  describe('secondary entry-point', () => {