block visual mode: literal tabs treated oddly

[fsiler]

Is this a hackmd.io issue?

• [X] Yes, the bug happens on https://hackmd.io
• [ ] No. If it's a self-hosted CodiMD instance, please fire up the issue in the repo of CodiMD: https://github.com/hackmdio/codimd

Read our Official tutorial

It's on https://hackmd.io/c/tutorials/

或是中文版 https://hackmd.io/c/tutorials-tw/

What's the problem

When in vim mode, Visual Block mode (ctrl+v) incorrectly manipulates tab characters as if they are of width one, rather than the width visually exposed.

Current behaviour

Screenshot (optional)

Provide steps to reproduce:

1. Create a document, such as a table, consisting of both tabs and spaces

  |
\t|

2. set to use Vim mode and enter command mode (esc)
3. gg to go to the top
4. ctrl+v to enter visual block mode
5. G to go to the bottom row
6. A to append. Notice that rather than a clean block selection, a jagged edge is selected.

example note

Expected behaviour

Tabs should be treated with their rendered width, not width one.

Environment

I use HackMD on:

Desktop

• OS: macOS and Windows
• Browser: Firefox
• Browser Version: 125

Mobile n/a

Additional context

n/a