ts-morph codefix for esm imports

esm-imports.cjs

const path = require('path');
const fs = require('fs');

const { Project, SyntaxKind } = require('ts-morph');

async function main() {
  const project = new Project();
  const glob = path.join(process.cwd(), './**/(src|test)/**/*.{ts,tsx,js}');
  project.addSourceFilesAtPaths(glob);

  project.getSourceFiles().forEach(async (sourceFile) => {
    const imports = sourceFile.getImportDeclarations();
    const expts = sourceFile.getExportDeclarations();
    const declarations = imports.concat(expts);
    if (!declarations.length) {
      return;
    }

    declarations.forEach((declaration) => {
      declaration.getDescendantsOfKind(SyntaxKind.StringLiteral).forEach((stringPath) => {
        const text = stringPath.getText().replace(/'/g, '');
        if (text.endsWith('.js')) return;
        // this represents paths to barrel files eg ('..')
        if (text.endsWith('.')) {
          stringPath.replaceWithText(`'${text}/index.js'`);
          return;
        }
        if (text.startsWith('.')) {
          const newPath = `'${text}.js'`;
          const filePath = path.join(sourceFile.getDirectoryPath(), `${text}/index.ts`);
          // second check is for js interop
          const exists = fs.existsSync(filePath) || fs.existsSync(filePath.replace('.ts', '.js'));

          stringPath.replaceWithText(exists ? `'${text}/index.js'` : newPath);
        }
      });
    });

    await sourceFile.save();
  });
}

main();