Implementing a VS Code feature: Research & Planning [1/2]

This is the first article in a series where we’ll implement “Copy with Imports” in VS Code’s TypeScript extension.

Previous article: Introduction

Next article: registerDocumentPasteEditProvider

To start with, some basic research:

• The issue we’re looking to fix is TypeScript#50187. This was originally filed as vscode#66236.
• The VS Code API we’ll need to hook into is registerDocumentPasteEditProvider.
• The API is still unstable/proposed, so we can’t publish an extension that uses these APIs, but we can test these changes locally.

The registerDocumentPasteEditProvider API takes three parameters:

• a DocumentSelector to specify which documents this provider should be used for
• a DocumentPasteEditProvider which is an interface containing two functions:
  • prepareDocumentPaste, which is invoked after the user copies text in a file.
  • provideDocumentPasteEdits, which is invoked when the user pastes text in a file.
• metadata which is an object that specifies whether the provider should be used for copy or paste

Here’s how I plan to break this down:

1. Call registerDocumentPasteEditProvider, but use a dummy implementation that just console.logs the arguments.
2. Implement the prepareDocumentPaste function to copy the imports along with the copied text.
3. Implement the provideDocumentPasteEdits function to insert the copied imports.