Allow Ability to Set Preference on Unused Import Removal

[rehatkathuria]

First of all: Thank you for your work on this! I have a habit of hitting CMD + S often as I'm writing code. Having the formatter organise and rearrange imports during those keystrokes is great –– however, having it remove an import that I haven't yet used is a little frustrating. I'd really appreciate the ability to disable that functionality.

[apexskier]

Looks like this might be possible. tsserver has a skipDestructiveCodeActions argument that skips the remove unused arguments logic.

https://github.com/microsoft/TypeScript/blob/663b19fe4a7c4d4ddaa61aedadd28da06acd27b6/src/services/organizeImports.ts#L91-L95

In order to implement this I'll need to pass that through from typescript-language-server as an argument here, which will require work in that codebase. It looks like for proper typing it'll also require upgrading typescript (from v3 to v4) in the codebase, which might be tricky.

Then I can pass an option from the extension here:

nova-typescript/src/commands/organizeImports.ts

Line 54 in 0d04b61

arguments: [editor.document.path],

[apexskier]

It looks like this feature will be new in TypeScript 4.4, which is still in beta currently:

microsoft/TypeScript#43184 / microsoft/TypeScript#43051

[apexskier]

Another option I'd recommend if you're looking to improve your experience is to disable organize imports on save through this extension and replace it with an ESLint rule that organizes imports, using https://github.com/apexskier/nova-eslint, and enabling eslint's fix on save.

[github-actions]

Included in release v2.6.0