tree-shaking-server-side-code-6.ts

import * as ts from 'typescript';
import { PLATFORM } from '@ngtools/webpack';

const replaceIsPlatformCallsTransformerFactory: ts.TransformerFactory<ts.SourceFile> = (
  context: ts.TransformationContext,
) => (sourceFile: ts.SourceFile) => {
  const visitCallExpression: ts.Visitor = (node: ts.Node) => {
    if (ts.isCallExpression(node) && ts.isIdentifier(node.expression)) {
      // If it's a call expression like `isPlatformServer(platformId)`.
      if (node.expression.escapedText === 'isPlatformServer') {
        return ts.factory.createFalse();
      } else if (node.expression.escapedText === 'isPlatformBrowser') {
        return ts.factory.createTrue();
      }
    }

    return ts.visitEachChild(node, visitCallExpression, context);
  };

  return ts.visitEachChild(sourceFile, visitCallExpression, context);
};