VS Code works well for me. Both TypeScript & VS Code are made by Microsoft so they work pretty well together.

Probably vscode or a Jetbrains IDE.

Personally I use Sublime these days, but Atom and Visual Studio Code are also excellent choices. I'd say they're all tied pretty closely for the leading spot, so the choice is really a matter of personal preference.

I've been using WebStorm on Windows and Linux, it is also available for macOS. Can really recommend all the JetBrains IDEs!

I personally use sublime. In-editor error messages and intelligent autocomplete are a godsend.

VSCode

VS Code is great.

But "best" is pretty subjective.