highlight-undo.nvim

Highlight changed text after any action which modifies the current buffer. This plugin was originaly written to support Undo / Redo highlighting, but is now expanded to support any other action.

Purely lua / nvim api implementation, no external dependencies needed.

In Action

Installation

Using Lazy:

  {
    'tzachar/highlight-undo.nvim',
    opts = {
      ...
    },
  },

Setup

You can manually setup highlight-undo as follows:

require('highlight-undo').setup({
  duration = 300,
  keymaps = {
    Keymap_name = {
      -- most fields here are the same as in vim.keymap.set
      desc = "a description",
      hlgroup = 'HighlightUndo',
      mode = 'n',
      lhs = 'lhs',
      rhs = 'optional, can be nil',
      opts = {
        -- same as opts to vim.keymap.set. if rhs is nil, there should be a
        -- callback key which points to a function
      },
    },
  },
})

Plugin Load Order

As this plugin hijacks kemaps, there might be issues with other plugin with similar behavior. Make sure this plugin is loaded last. For example, using lazy.nvim, you can just specify the following:

  {
    'tzachar/highlight-undo.nvim',
    keys = { { "u" }, { "<C-r>" } },
  }

Keymaps

Specify which keymaps should trigger the beginning and end of tracking changes (see here). By default, the plugin starts tracking changes before and after the following keymaps:

• u -- for Undo
• <C-r> -- for Redo
• p -- for paste
• P -- for Paste

To disable any of the defaults, add a disabled = true entry to the appropirate keymap. For example, to disable the default highlight for Paste:

require('highlight-undo').setup({
  keymaps = {
    Paste = {
        disabled = true,
    },
  },
})

Keymaps are specified in the same format as vim.keymap.set accepts: mode, lhs, rhs, opts. Maps are passed verbatim to vim.keymap.set. A different possibility is when you just want to hijack an existing keymap, you can then just specify the lhs and highligh-undo will remap lhs and trigger the original action afterwards.

For example, adding p (which exists by default), is as easy as:

require('highlight-undo').setup({
  keymaps = {
    paste = {
      desc = "paste",
      hlgroup = 'HighlightUndo',
      mode = 'n',
      lhs = 'p',
      rhs = 'p',
      opts = {},
    },
  },
})

Note that lhs and rhs are identical.

hlgroup

Specify the highlighting group to use.

By default, highlight-undo will use HighlightUndo for the undo action and HighlightRedo for the redo action. Both of these groups, are defined when the plugin is loaded. If the groups are already defined elsewhere in your config then they will not be overwritten. You can also use others groups, if desired.

duration

The duration (in milliseconds) to highlight changes. Default is 300.

How the Plugin Works

highlight-undo will remap the u and <C-r> keys (for undo and redo, by default) and hijack the calls. By utilizing nvim_buf_attach to get indications for changes in the buffer, the plugin can achieve very low overhead.