chore: Fix/update markdown preview esm

[iennae]

Description

Fixes #

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Checklist

• I have followed guidelines from CONTRIBUTING.MD and Samples Style Guide
• Tests pass: npm test (see Testing)
• Lint pass: npm run lint (see Style)
• These samples need a new API enabled in testing projects to pass (let us know which ones)
• These samples need a new/updated env vars in testing projects set to pass (let us know which ones)
• This pull request is from a branch created directly off of GoogleCloudPlatform/nodejs-docs-samples. Not a fork.
• This sample adds a new sample directory, and I updated the CODEOWNERS file with the codeowners for this sample
• This sample adds a new sample directory, and I created GitHub Actions workflow for this sample
• This sample adds a new Product API, and I updated the Blunderbuss issue/PR auto-assigner with the codeowners for this sample
• Please merge this PR for me once it is approved

[gemini-code-assist]

Hello @iennae, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

Summary of Changes

This pull request updates the Markdown Preview application to use ES modules instead of CommonJS modules. This involves changing require statements to import statements, updating the package.json file to specify type: module, and adjusting the export syntax. Additionally, the got dependency is updated to version 14.0.0, handlebars to 4.7.8, express to 4.18.2, and markdown-it to 14.0.0. The request timeout for rendering markdown has also been increased from 3000ms to 10000ms.

Highlights

• ES Module Conversion: The application has been converted to use ES modules, replacing require with import and updating export syntax.
• Dependency Updates: Several dependencies have been updated, including got, handlebars, express, and markdown-it to their latest versions.
• Request Timeout Increase: The timeout for rendering markdown has been increased to 10 seconds to prevent request timeouts.

Changelog

Click here to see the changelog

• run/markdown-preview/editor/app.js
  • Replaced require statements with import statements for dependencies.
  • Modified the buildRenderedHtml function to include process.cwd() for file paths.
  • Changed module.exports to export default app.
• run/markdown-preview/editor/index.js
  • Replaced require statements with import statements.
  • Used fs.readFileSync to read package.json as ES modules do not directly support importing JSON files.
• run/markdown-preview/editor/package.json
  • Added type: module to enable ES module support.
  • Updated got dependency to ^14.0.0 and handlebars to ^4.7.8.
• run/markdown-preview/editor/render.js
  • Replaced require statements with import statements.
  • Increased the request timeout to 10000ms.
  • Changed module.exports to export default renderRequest.
• run/markdown-preview/editor/test/app.test.js
  • Replaced require statements with import statements.
  • Removed path require and directly imported app and buildRenderedHtml
  • Removed 'use strict' declaration.
• run/markdown-preview/editor/test/system.test.js
  • Replaced require statements with import statements.
• run/markdown-preview/renderer/app.js
  • Replaced require statements with import statements.
  • Changed module.exports to export default app.
• run/markdown-preview/renderer/index.js
  • Replaced require statements with import statements.
  • Used fs.readFileSync to read package.json.
• run/markdown-preview/renderer/package.json
  • Added type: module to enable ES module support.
  • Updated express dependency to ^4.18.2, markdown-it to ^14.0.0, and got to ^14.0.0.
• run/markdown-preview/renderer/test/app.test.js
  • Replaced require statements with import statements.
  • Removed path require and directly imported app
  • Removed 'use strict' declaration.
• run/markdown-preview/renderer/test/system.test.js
  • Replaced require statements with import statements.

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[gemini-code-assist]

Code Review

The pull request updates the markdown preview to use ESM modules. This involves changing require statements to import statements, updating dependencies, and adding type: module to the package.json files. The changes look good overall, but I have a few suggestions for improvement.

Summary of Findings

• Consistency in imports: The pull request mixes named and default imports. For example, in run/markdown-preview/editor/app.js, express and handlebars are imported as default imports, while renderRequest is imported as a named import. It would be better to be consistent and use either named or default imports throughout the codebase.
• Error handling in buildRenderedHtml: The error handling in the buildRenderedHtml function could be improved. Currently, it throws a generic Error object with a message. It would be better to throw a more specific error type or include more information about the error.
• Redundant variable assignment: In run/markdown-preview/editor/app.js, the renderedHtml variable is assigned the result of compiledTemplate({default: markdownDefault}) and then immediately returned. This can be simplified by directly returning the result of the function call.

Merge Readiness

The pull request is almost ready to be merged. However, I recommend addressing the comments regarding consistency in imports, error handling in buildRenderedHtml, and the redundant variable assignment before merging. I am unable to approve this pull request, and recommend that others review and approve this code before merging.