diff --git a/.github/workflows/pr_check.yml b/.github/workflows/pr_check.yml
index 5a82f41..a4fe05a 100644
--- a/.github/workflows/pr_check.yml
+++ b/.github/workflows/pr_check.yml
@@ -8,27 +8,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@master
-      - uses: JohnnyMorganz/stylua-action@v1.1.2
+      - uses: JohnnyMorganz/stylua-action@v4
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
+          version: latest
           args: --check lua
 
   luacheck:
     runs-on: ubuntu-latest
-
     steps:
-      - uses: actions/checkout@master
-
-      - uses: leafo/gh-actions-lua@v8.0.0
-        with:
-          luaVersion: 'luajit-2.1.0-beta3'
-
-      - uses: leafo/gh-actions-luarocks@v4.0.0
-
-      - name: build
-        run: |
-          luarocks install luacheck
-
-      - name: test
-        run: |
-          luacheck lua
+      - uses: lunarmodules/luacheck@v1.2.0
diff --git a/lua/formatter/defaults/alejandra.lua b/lua/formatter/defaults/alejandra.lua
index 162c1a7..9f23214 100644
--- a/lua/formatter/defaults/alejandra.lua
+++ b/lua/formatter/defaults/alejandra.lua
@@ -2,6 +2,6 @@ return function()
   return {
     exe = "alejandra",
     stdin = true,
-    args = {"--quiet"},
+    args = { "--quiet" },
   }
 end
diff --git a/lua/formatter/defaults/biome.lua b/lua/formatter/defaults/biome.lua
index 3264ad2..33f0c6d 100644
--- a/lua/formatter/defaults/biome.lua
+++ b/lua/formatter/defaults/biome.lua
@@ -4,10 +4,10 @@ return function()
   return {
     exe = "biome",
     args = {
-        "format",
-        "--stdin-file-path",
-        util.escape_path(util.get_current_buffer_file_path()),
+      "format",
+      "--stdin-file-path",
+      util.escape_path(util.get_current_buffer_file_path()),
     },
     stdin = true,
   }
-end
\ No newline at end of file
+end
diff --git a/lua/formatter/defaults/ktlint.lua b/lua/formatter/defaults/ktlint.lua
index 922c98f..22eb2ff 100644
--- a/lua/formatter/defaults/ktlint.lua
+++ b/lua/formatter/defaults/ktlint.lua
@@ -1,13 +1,11 @@
-local util = require "formatter.util"
-
 return function()
-    return {
-        exe = "ktlint",
-        args = {
-            "--stdin",
-            "--format",
-            "--log-level=none"
-        },
-        stdin = true
-    }
+  return {
+    exe = "ktlint",
+    args = {
+      "--stdin",
+      "--format",
+      "--log-level=none",
+    },
+    stdin = true,
+  }
 end
diff --git a/lua/formatter/defaults/ocamlformat.lua b/lua/formatter/defaults/ocamlformat.lua
index 05666d6..5dd0115 100644
--- a/lua/formatter/defaults/ocamlformat.lua
+++ b/lua/formatter/defaults/ocamlformat.lua
@@ -6,7 +6,7 @@ return function()
       "--enable-outside-detected-project",
       "--name",
       util.escape_path(util.get_current_buffer_file_name()),
-      "-"
+      "-",
     },
     stdin = true,
   }
diff --git a/lua/formatter/defaults/stylish_haskell.lua b/lua/formatter/defaults/stylish_haskell.lua
index 15889a6..5d4f194 100644
--- a/lua/formatter/defaults/stylish_haskell.lua
+++ b/lua/formatter/defaults/stylish_haskell.lua
@@ -1,5 +1,3 @@
-local util = require "formatter.util"
-
 return function()
   return {
     exe = "stylish-haskell",
diff --git a/lua/formatter/filetypes/java.lua b/lua/formatter/filetypes/java.lua
index 3d24276..93eccb4 100644
--- a/lua/formatter/filetypes/java.lua
+++ b/lua/formatter/filetypes/java.lua
@@ -3,11 +3,11 @@ local M = {}
 local util = require "formatter.util"
 
 function M.clangformat()
-    return {
-        exe = "clang-format",
-        args = {"--assume-filename=.java"},
-        stdin = true
-    }
+  return {
+    exe = "clang-format",
+    args = { "--assume-filename=.java" },
+    stdin = true,
+  }
 end
 
 function M.ideaformat()
@@ -18,17 +18,16 @@ function M.ideaformat()
   }
 end
 
-
 function M.google_java_format()
-    return {
-        exe = "google-java-format",
-        args = {
-            "--aosp",
-            util.escape_path(util.get_current_buffer_file_path()),
-            "--replace"
-        },
-        stdin = true
-    }
+  return {
+    exe = "google-java-format",
+    args = {
+      "--aosp",
+      util.escape_path(util.get_current_buffer_file_path()),
+      "--replace",
+    },
+    stdin = true,
+  }
 end
 
 return M
diff --git a/lua/formatter/filetypes/kotlin.lua b/lua/formatter/filetypes/kotlin.lua
index 2065dcd..49155ca 100644
--- a/lua/formatter/filetypes/kotlin.lua
+++ b/lua/formatter/filetypes/kotlin.lua
@@ -1,15 +1,15 @@
 local M = {}
 
 function M.ktlint()
-    return {
-        exe = "ktlint",
-        args = {
-            "--stdin",
-            "--format",
-            "--log-level=none"
-        },
-        stdin = true
-    }
+  return {
+    exe = "ktlint",
+    args = {
+      "--stdin",
+      "--format",
+      "--log-level=none",
+    },
+    stdin = true,
+  }
 end
 
 return M
diff --git a/lua/formatter/filetypes/liquidsoap.lua b/lua/formatter/filetypes/liquidsoap.lua
index 7f21f9c..e8b6d71 100644
--- a/lua/formatter/filetypes/liquidsoap.lua
+++ b/lua/formatter/filetypes/liquidsoap.lua
@@ -3,8 +3,8 @@ local M = {}
 function M.liquidsoap_prettier()
   return {
     exe = "liquidsoap-prettier",
-    args = {"--write"},
-    stdin = false
+    args = { "--write" },
+    stdin = false,
   }
 end
 
diff --git a/lua/formatter/filetypes/lua.lua b/lua/formatter/filetypes/lua.lua
index 741c02c..a8eddef 100644
--- a/lua/formatter/filetypes/lua.lua
+++ b/lua/formatter/filetypes/lua.lua
@@ -19,8 +19,8 @@ end
 function M.luaformat()
   return {
     exe = "lua-format",
-    args = {util.escape_path(util.get_current_buffer_file_path())},
-    stdin = true
+    args = { util.escape_path(util.get_current_buffer_file_path()) },
+    stdin = true,
   }
 end
 
diff --git a/lua/formatter/filetypes/proto.lua b/lua/formatter/filetypes/proto.lua
index 4d7cb36..532fd16 100644
--- a/lua/formatter/filetypes/proto.lua
+++ b/lua/formatter/filetypes/proto.lua
@@ -4,7 +4,7 @@ function M.buf_format()
   return {
     exe = "buf format",
     args = {
-      '-w',
+      "-w",
     },
     stdin = false,
   }
diff --git a/lua/formatter/filetypes/python.lua b/lua/formatter/filetypes/python.lua
index 577c1fb..1b359f0 100644
--- a/lua/formatter/filetypes/python.lua
+++ b/lua/formatter/filetypes/python.lua
@@ -16,10 +16,15 @@ function M.autopep8()
 end
 
 function M.isort()
-  local util = require("formatter.util")
+  local util = require "formatter.util"
   return {
     exe = "isort",
-    args = { "-q", "--filename", util.escape_path(util.get_current_buffer_file_path()), "-" },
+    args = {
+      "-q",
+      "--filename",
+      util.escape_path(util.get_current_buffer_file_path()),
+      "-",
+    },
     stdin = true,
   }
 end
@@ -33,10 +38,15 @@ function M.docformatter()
 end
 
 function M.black()
-  local util = require("formatter.util")
+  local util = require "formatter.util"
   return {
     exe = "black",
-    args = { "-q", "--stdin-filename", util.escape_path(util.get_current_buffer_file_name()), "-" },
+    args = {
+      "-q",
+      "--stdin-filename",
+      util.escape_path(util.get_current_buffer_file_name()),
+      "-",
+    },
     stdin = true,
   }
 end
diff --git a/lua/formatter/filetypes/toml.lua b/lua/formatter/filetypes/toml.lua
index 4de29dd..a2a6f3a 100644
--- a/lua/formatter/filetypes/toml.lua
+++ b/lua/formatter/filetypes/toml.lua
@@ -1,10 +1,15 @@
 local M = {}
 
 function M.taplo()
-  local util = require("formatter.util")
+  local util = require "formatter.util"
   return {
     exe = "taplo",
-    args = { "fmt", "--stdin-filepath", util.escape_path(util.get_current_buffer_file_path()),"-" },
+    args = {
+      "fmt",
+      "--stdin-filepath",
+      util.escape_path(util.get_current_buffer_file_path()),
+      "-",
+    },
     stdin = true,
     try_node_modules = true,
   }
diff --git a/lua/formatter/format.lua b/lua/formatter/format.lua
index 8dd7e0c..7d8dfc3 100644
--- a/lua/formatter/format.lua
+++ b/lua/formatter/format.lua
@@ -134,7 +134,8 @@ function M.start_task(configs, start_line, end_line, opts)
     end
 
     if opts.lock then
-      vim.api.nvim_buf_set_option(bufnr, "modifiable", false)
+      vim.api.nvim_set_option_value("modifiable", false, { buf = bufnr })
+      -- vim.api.nvim_buf_set_option(bufnr, "modifiable", false)
     end
 
     name = current.name
@@ -179,7 +180,7 @@ function M.start_task(configs, start_line, end_line, opts)
         if binpath then
           try_node_modules_path = binpath
             .. util.path_separator
-            .. vim.fn.getenv("PATH")
+            .. vim.fn.getenv "PATH"
         else
           try_node_modules_path = false
         end
@@ -232,7 +233,8 @@ function M.start_task(configs, start_line, end_line, opts)
     end
 
     if opts.lock then
-      vim.api.nvim_buf_set_option(bufnr, "modifiable", true)
+      -- vim.api.nvim_buf_set_option(bufnr, "modifiable", true)
+      vim.api.nvim_set_option_value("modifiable", true, { buf = bufnr })
     end
 
     if not util.is_same(input, output) then
@@ -247,7 +249,8 @@ function M.start_task(configs, start_line, end_line, opts)
         )
         return
       end
-      util.set_lines(bufnr, start_line, end_line, output)
+      util.update_lines(bufnr, input, output)
+
       util.restore_view_per_window(window_to_view)
 
       if opts.write and bufnr == vim.api.nvim_get_current_buf() then
diff --git a/lua/formatter/util.lua b/lua/formatter/util.lua
index 910369b..8f2bc81 100644
--- a/lua/formatter/util.lua
+++ b/lua/formatter/util.lua
@@ -1,184 +1,334 @@
 local M = {}
-
-local config = require("formatter.config")
+local config = require "formatter.config"
 
 -- NOTE: to contributors
 -- NOTE: use these for "lua/formatter/defaults" and "lua/formatter/filetypes"
 
 function M.get_cwd()
-    return vim.fn.getcwd()
+  return vim.fn.getcwd()
 end
 
 function M.get_current_buffer_file_path()
-    return vim.api.nvim_buf_get_name(0)
+  return vim.api.nvim_buf_get_name(0)
 end
 
 function M.get_current_buffer_file_name()
-    return vim.fn.fnamemodify(M.get_current_buffer_file_path(), ":t")
+  return vim.fn.fnamemodify(M.get_current_buffer_file_path(), ":t")
 end
 
 function M.get_current_buffer_file_dir()
-    return vim.fn.fnamemodify(M.get_current_buffer_file_path(), ":h")
+  return vim.fn.fnamemodify(M.get_current_buffer_file_path(), ":h")
 end
 
 function M.get_current_buffer_file_extension()
-    return vim.fn.fnamemodify(M.get_current_buffer_file_path(), ":e")
+  return vim.fn.fnamemodify(M.get_current_buffer_file_path(), ":e")
 end
 
 function M.quote_cmd_arg(arg)
-    return string.format("'%s'", arg)
+  return string.format("'%s'", arg)
 end
 
 -- TODO: check fnameescape or shellescape?
 function M.escape_path(arg)
-    return vim.fn.shellescape(arg, true)
+  return vim.fn.shellescape(arg, true)
 end
 
 function M.wrap_sed_replace(pattern, replacement, flags)
-    return string.format("s/%s/%s/%s", pattern, replacement or "", flags or "")
+  return string.format("s/%s/%s/%s", pattern, replacement or "", flags or "")
 end
 
 -- TODO: check that this is okay for paths and ordinary strings
 function M.format_prettydiff_arg(name, value)
-    return string.format('%s:"%s"', name, value)
+  return string.format('%s:"%s"', name, value)
 end
 
 -- Returns a list of currently available formatters for the specified filetype.
 function M.get_available_formatters_for_ft(ft)
-    local available_formatters = {}
-    local user_defined_formatters = config.values.filetype
-
-    for formatter_filetype, formatter_functions in pairs(user_defined_formatters) do
-        if ft == "*" or ft == formatter_filetype then
-            for _, formatter_function in ipairs(formatter_functions) do
-                local formatter_info = formatter_function()
-                table.insert(available_formatters, formatter_info)
-            end
-        end
+  local available_formatters = {}
+  local user_defined_formatters = config.values.filetype
+
+  for formatter_filetype, formatter_functions in pairs(user_defined_formatters) do
+    if ft == "*" or ft == formatter_filetype then
+      for _, formatter_function in ipairs(formatter_functions) do
+        local formatter_info = formatter_function()
+        table.insert(available_formatters, formatter_info)
+      end
     end
+  end
 
-    return available_formatters
+  return available_formatters
 end
 
 -- NOTE: to contributors
 -- NOTE: use these for "lua/formatter/filetypes"
 
 function M.withl(f, ...)
-    local argsl = { ... }
-    return function(...)
-        local argsr = { ... }
-        return f(unpack(argsl), unpack(argsr))
-    end
+  local argsl = { ... }
+  return function(...)
+    local argsr = { ... }
+    return f(unpack(argsl), unpack(argsr))
+  end
 end
 
 function M.withr(f, ...)
-    local argsr = { ... }
-    return function(...)
-        local argsl = { ... }
-        return f(unpack(argsl), unpack(argsr))
-    end
+  local argsr = { ... }
+  return function(...)
+    local argsl = { ... }
+    return f(unpack(argsl), unpack(argsr))
+  end
 end
 
 function M.copyf(f)
-    return function(...)
-        return f(...)
-    end
+  return function(...)
+    return f(...)
+  end
 end
 
 -----------------------------------------------------------------------------
 -- Tables
 
 function M.is_empty(s)
-    if type(s) == "table" then
-        for _, v in pairs(s) do
-            if not M.is_empty(v) then
-                return false
-            end
-        end
-        return true
+  if type(s) == "table" then
+    for _, v in pairs(s) do
+      if not M.is_empty(v) then
+        return false
+      end
     end
-    return s == nil or s == ""
+    return true
+  end
+  return s == nil or s == ""
 end
 
 function M.split(s, sep, plain)
-    if s ~= "" then
-        local t = {}
-        for c in vim.gsplit(s, sep, plain) do
-            t[c] = true
-        end
-        return t
+  if s ~= "" then
+    local t = {}
+    for c in vim.gsplit(s, sep, plain) do
+      t[c] = true
     end
+    return t
+  end
 end
 
 function M.is_same(a, b)
-    if type(a) ~= type(b) then
-        return false
+  if type(a) ~= type(b) then
+    return false
+  end
+  if type(a) == "table" then
+    if #a ~= #b then
+      return false
     end
-    if type(a) == "table" then
-        if #a ~= #b then
-            return false
-        end
-        for k, v in pairs(a) do
-            if not M.is_same(b[k], v) then
-                return false
-            end
-        end
-        return true
-    else
-        return a == b
+    for k, v in pairs(a) do
+      if not M.is_same(b[k], v) then
+        return false
+      end
     end
+    return true
+  else
+    return a == b
+  end
+end
+
+function M.tbl_slice(tbl, start_idx, end_idx)
+  local ret = {}
+  if not start_idx then
+    start_idx = 1
+  end
+  if not end_idx then
+    end_idx = #tbl
+  end
+  for i = start_idx, end_idx do
+    table.insert(ret, tbl[i])
+  end
+  return ret
 end
 
 -----------------------------------------------------------------------------
 -- Vim
 
 function M.set_lines(bufnr, startLine, endLine, lines)
-    return vim.api.nvim_buf_set_lines(bufnr, startLine, endLine, false, lines)
+  return vim.api.nvim_buf_set_lines(bufnr, startLine, endLine, false, lines)
+end
+
+local function common_prefix_len(a, b)
+  if not a or not b then
+    return 0
+  end
+  local min_len = math.min(#a, #b)
+  for i = 1, min_len do
+    if string.byte(a, i) ~= string.byte(b, i) then
+      return i - 1
+    end
+  end
+  return min_len
+end
+
+local function common_suffix_len(a, b)
+  local a_len = #a
+  local b_len = #b
+  local min_len = math.min(a_len, b_len)
+  for i = 0, min_len - 1 do
+    if string.byte(a, a_len - i) ~= string.byte(b, b_len - i) then
+      return i
+    end
+  end
+  return min_len
+end
+
+local function create_text_edit(
+  original_lines,
+  replacement,
+  is_insert,
+  is_replace,
+  orig_line_start,
+  orig_line_end
+)
+  local start_line, end_line = orig_line_start - 1, orig_line_end - 1
+  local start_char, end_char = 0, 0
+  if is_replace then
+    -- If we're replacing text, see if we can avoid replacing the entire line
+    start_char =
+      common_prefix_len(original_lines[orig_line_start], replacement[1])
+    if start_char > 0 then
+      replacement[1] = replacement[1]:sub(start_char + 1)
+    end
+
+    if original_lines[orig_line_end] then
+      local last_line = replacement[#replacement]
+      local suffix = common_suffix_len(original_lines[orig_line_end], last_line)
+      -- If we're only replacing one line, make sure the prefix/suffix calculations don't overlap
+      if orig_line_end == orig_line_start then
+        suffix =
+          math.min(suffix, original_lines[orig_line_end]:len() - start_char)
+      end
+      end_char = original_lines[orig_line_end]:len() - suffix
+      if suffix > 0 then
+        replacement[#replacement] = last_line:sub(1, last_line:len() - suffix)
+      end
+    end
+  end
+  -- If we're inserting text, make sure the text includes a newline at the end.
+  -- The one exception is if we're inserting at the end of the file, in which case the newline is
+  -- implicit
+  if is_insert and start_line < #original_lines then
+    table.insert(replacement, "")
+  end
+  local new_text = table.concat(replacement, "\n")
+
+  return {
+    newText = new_text,
+    range = {
+      start = {
+        line = start_line,
+        character = start_char,
+      },
+      ["end"] = {
+        line = end_line,
+        character = end_char,
+      },
+    },
+  }
+end
+
+function M.update_lines(bufnr, original_lines, new_lines)
+  -- Update lines based on diffs. This is based (copied) from conform with some edits
+  table.insert(original_lines, "")
+  table.insert(new_lines, "")
+  local original_text = table.concat(original_lines, "\n")
+  local new_text = table.concat(new_lines, "\n")
+  table.remove(original_lines)
+  table.remove(new_lines)
+
+  if new_text:match "^%s*$" and not original_text:match "^%s*$" then
+    return false
+  end
+
+  ---@diagnostic disable-next-line: missing-fields
+  local indices = vim.diff(original_text, new_text, {
+    result_type = "indices",
+    algorithm = "histogram",
+  })
+  assert(type(indices) == "table")
+  local text_edits = {}
+  for _, idx in ipairs(indices) do
+    local orig_line_start, orig_line_count, new_line_start, new_line_count =
+      unpack(idx)
+    local is_insert = orig_line_count == 0
+    local is_delete = new_line_count == 0
+    local is_replace = not is_insert and not is_delete
+    local orig_line_end = orig_line_start + orig_line_count
+    local new_line_end = new_line_start + new_line_count
+
+    if is_insert then
+      orig_line_start = orig_line_start + 1
+      orig_line_end = orig_line_end + 1
+    end
+
+    local replacement = M.tbl_slice(new_lines, new_line_start, new_line_end - 1)
+
+    if is_replace then
+      orig_line_end = orig_line_end - 1
+    end
+    local text_edit = create_text_edit(
+      original_lines,
+      replacement,
+      is_insert,
+      is_replace,
+      orig_line_start,
+      orig_line_end
+    )
+    table.insert(text_edits, text_edit)
+  end
+
+  vim.lsp.util.apply_text_edits(text_edits, bufnr, "utf-8")
+
+  return not vim.tbl_isempty(text_edits)
 end
 
 function M.get_lines(bufnr, startLine, endLine)
-    return vim.api.nvim_buf_get_lines(bufnr, startLine, endLine, false)
+  return vim.api.nvim_buf_get_lines(bufnr, startLine, endLine, false)
 end
 
 function M.fire_event(event, silent)
-    local cmd = string.format(
-        "%s doautocmd <nomodeline> User %s",
-        silent and "silent" or "",
-        event
-    )
-    vim.api.nvim_command(cmd)
+  local cmd = string.format(
+    "%s doautocmd <nomodeline> User %s",
+    silent and "silent" or "",
+    event
+  )
+  vim.api.nvim_command(cmd)
 end
 
 function M.get_buffer_variable(buf, var)
-    local status, result = pcall(vim.api.nvim_buf_get_var, buf, var)
-    if status then
-        return result
-    end
-    return nil
+  local status, result = pcall(vim.api.nvim_buf_get_var, buf, var)
+  if status then
+    return result
+  end
+  return nil
 end
 
 --- get a table that maps a window to a view
 ---@see vim.fn.winsaveview()
 function M.get_views_for_this_buffer()
-    local windows_containing_this_buffer = vim.fn.win_findbuf(vim.fn.bufnr())
-    local window_to_view = {}
-    for _, w in ipairs(windows_containing_this_buffer) do
-        vim.api.nvim_win_call(w, function()
-            window_to_view[w] = vim.fn.winsaveview()
-        end)
-    end
-    return window_to_view
+  local windows_containing_this_buffer = vim.fn.win_findbuf(vim.fn.bufnr())
+  local window_to_view = {}
+  for _, w in ipairs(windows_containing_this_buffer) do
+    vim.api.nvim_win_call(w, function()
+      window_to_view[w] = vim.fn.winsaveview()
+    end)
+  end
+  return window_to_view
 end
 
 --- restore view for each window
 ---@param window_to_view table maps window to a view
 ---@see vim.fn.winrestview()
 function M.restore_view_per_window(window_to_view)
-    for w, view in pairs(window_to_view) do
-        if vim.api.nvim_win_is_valid(w) then
-            vim.api.nvim_win_call(w, function() vim.fn.winrestview(view) end)
-        end
+  for w, view in pairs(window_to_view) do
+    if vim.api.nvim_win_is_valid(w) then
+      vim.api.nvim_win_call(w, function()
+        vim.fn.winrestview(view)
+      end)
     end
+  end
 end
 
 --- Find the closest node_modules path
@@ -203,7 +353,7 @@ function M.get_node_modules_bin_path(node_modules)
   return bin_path
 end
 
-if vim.fn.has("win32") == 1 then
+if vim.fn.has "win32" == 1 then
   M.path_separator = ";"
 else
   M.path_separator = ":"