Test under Node v18 in CI

[ddzz]

Suggestion

Node v18 was released recently. TypeScript should be tested under this version in CI.

🔍 Search Terms

Node, Node 18.x, continuous integration, CI, GitHub Actions

✅ Viability Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, new syntax sugar for JS, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

⭐ Suggestion

Node v18 was released recently. TypeScript should be tested under this version in CI.

📃 Motivating Example

Running tests in CI under Node v18 shows that TypeScript works with the latest version of Node.

💻 Use Cases

Coverage of all major Node versions in CI.