remove-platform-server-exports.ts

/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

import { DirEntry, Rule, UpdateRecorder } from '@angular-devkit/schematics';
import * as ts from '../../third_party/github.com/Microsoft/TypeScript/lib/typescript';

function* visit(directory: DirEntry): IterableIterator<ts.SourceFile> {
  for (const path of directory.subfiles) {
    if (path.endsWith('.ts') && !path.endsWith('.d.ts')) {
      const entry = directory.file(path);
      if (entry) {
        const content = entry.content;
        if (content.includes('@angular/platform-server') && content.includes('renderModule')) {
          const source = ts.createSourceFile(
            entry.path,
            content.toString().replace(/^\uFEFF/, ''),
            ts.ScriptTarget.Latest,
            true,
          );

          yield source;
        }
      }
    }
  }

  for (const path of directory.subdirs) {
    if (path === 'node_modules' || path.startsWith('.')) {
      continue;
    }

    yield* visit(directory.dir(path));
  }
}

export default function (): Rule {
  return (tree) => {
    for (const sourceFile of visit(tree.root)) {
      let recorder: UpdateRecorder | undefined;
      let printer: ts.Printer | undefined;

      ts.forEachChild(sourceFile, function analyze(node) {
        if (
          !(
            ts.isExportDeclaration(node) &&
            node.moduleSpecifier &&
            ts.isStringLiteral(node.moduleSpecifier) &&
            node.moduleSpecifier.text === '@angular/platform-server' &&
            node.exportClause &&
            ts.isNamedExports(node.exportClause)
          )
        ) {
          // Not a @angular/platform-server named export.
          return;
        }

        const exportClause = node.exportClause;
        const newElements: ts.ExportSpecifier[] = [];
        for (const element of exportClause.elements) {
          if (element.name.text !== 'renderModule') {
            newElements.push(element);
          }
        }

        if (newElements.length === exportClause.elements.length) {
          // No changes
          return;
        }

        recorder ??= tree.beginUpdate(sourceFile.fileName);

        if (newElements.length) {
          // Update named exports as there are leftovers.
          const newExportClause = ts.factory.updateNamedExports(exportClause, newElements);
          printer ??= ts.createPrinter();
          const fix = printer.printNode(ts.EmitHint.Unspecified, newExportClause, sourceFile);

          const index = exportClause.getStart();
          const length = exportClause.getWidth();
          recorder.remove(index, length).insertLeft(index, fix);
        } else {
          // Delete export as no exports remain.
          recorder.remove(node.getStart(), node.getWidth());
        }

        ts.forEachChild(node, analyze);
      });

      if (recorder) {
        tree.commitUpdate(recorder);
      }
    }
  };
}