diff --git a/lua/outline/config.lua b/lua/outline/config.lua
index 0d8988c..d1f3f6b 100644
--- a/lua/outline/config.lua
+++ b/lua/outline/config.lua
@@ -326,6 +326,12 @@ function M.resolve_config()
   if type(au.only) ~= 'number' then
     au.only = (au.only and 1) or 0
   end
+  ----- KEYMAPS -----
+  for action, keys in pairs(M.o.keymaps) do
+    if type(keys) == 'string' then
+      M.o.keymaps[action] = { keys }
+    end
+  end
 end
 
 ---Ensure l is either table, false, or nil. If not, print warning using given
diff --git a/lua/outline/highlight.lua b/lua/outline/highlight.lua
index c9f2401..d95f310 100644
--- a/lua/outline/highlight.lua
+++ b/lua/outline/highlight.lua
@@ -1,38 +1,102 @@
-local M = {}
+local M = {
+  ns = {
+    hover = vim.api.nvim_create_namespace('outline-current'),
+    items = vim.api.nvim_create_namespace('outline-items-highlight'),
+    vt = vim.api.nvim_create_namespace('outline-virt-text'),
+  },
+}
 
-M.hovered_hl_ns = vim.api.nvim_create_namespace('hovered_item')
+---Clear all highlights in buffer
+---@param bufnr integer
+function M.clear_all_ns(bufnr)
+  vim.api.nvim_buf_clear_namespace(bufnr, -1, 0, -1)
+end
 
-function M.clear_hover_highlight(bufnr)
-  vim.api.nvim_buf_clear_namespace(bufnr, M.hovered_hl_ns, 0, -1)
+---Clear hover highlights in buffer
+---@param bufnr integer
+function M.clear_hovers(bufnr)
+  vim.api.nvim_buf_clear_namespace(bufnr, M.ns.hover, 0, -1)
 end
 
-function M.add_hover_highlight(bufnr, line, col_start)
-  vim.api.nvim_buf_add_highlight(bufnr, M.hovered_hl_ns, 'OutlineCurrent', line, col_start, -1)
+---Add single hover highlights
+---@param bufnr integer
+---@param nodes outline.FlatSymbolNode[]
+function M.hovers(bufnr, nodes)
+  for line, node in ipairs(nodes) do
+    if node.hovered then
+      vim.api.nvim_buf_add_highlight(bufnr, M.ns.hover, 'OutlineCurrent', line - 1, node.prefix_length, -1)
+    end
+  end
 end
 
-local get_hl_by_name
+---Add list of highlights `hl` for outline items
+---@param bufnr integer
+---@param hl_list outline.HL[]
+function M.items(bufnr, hl_list)
+  for _, h in ipairs(hl_list) do
+    -- stylua: ignore start
+    vim.api.nvim_buf_add_highlight(
+      bufnr, M.ns.items,
+      h.name, h.line - 1, h.from, h.to
+    )
+    -- stylua: ignore end
+  end
+end
 
-if vim.fn.has('nvim-0.9') == 1 then
-  get_hl_by_name = function(name)
-    local hl = vim.api.nvim_get_hl(0, { name = name, link = false })
-    return { fg = hl.fg, bg = hl.bg, ctermfg = hl.ctermfg, ctermbg = hl.ctermbg }
+---Add details virtual text
+---@param bufnr integer Outline buffer
+---@param details string[] Virtual text to add
+function M.details(bufnr, details)
+  for index, detail in ipairs(details) do
+    vim.api.nvim_buf_set_extmark(bufnr, M.ns.vt, index - 1, -1, {
+      virt_text = { { detail, 'OutlineDetails' } },
+      virt_text_pos = 'eol',
+      hl_mode = 'combine',
+    })
   end
-else
-  get_hl_by_name = function(name)
-    ---@diagnostic disable-next-line undefined-field
-    local hlrgb = vim.api.nvim_get_hl_by_name(name, true)
-    ---@diagnostic disable-next-line undefined-field
-    local hl = vim.api.nvim_get_hl_by_name(name, false)
-    return {
-      fg = hlrgb.foreground,
-      bg = hlrgb.background,
-      ctermfg = hl.foreground,
-      ctermbg = hl.background,
-    }
+end
+
+---Add linenos virtual text
+---@param bufnr integer Outline buffer
+---@param linenos string[] Must already be padded
+---@param hl_mode string Valid value for `buf_set_extmark` option `hl_mode`
+function M.linenos(bufnr, linenos, hl_mode)
+  -- TODO: Fix lineno not appearing if text in line is truncated on the right
+  -- due to narrow window, after nvim fixes virt_text_hide.
+  for index, lineno in ipairs(linenos) do
+    vim.api.nvim_buf_set_extmark(bufnr, M.ns.vt, index - 1, -1, {
+      virt_text = { { lineno, 'OutlineLineno' } },
+      virt_text_pos = 'overlay',
+      virt_text_win_col = 0,
+      hl_mode = hl_mode,
+    })
   end
 end
 
-function M.setup_highlights()
+---Create Outline highlights with default values if they don't already exist
+function M.setup()
+  local get_hl_by_name
+
+  if _G._outline_nvim_has[9] then
+    get_hl_by_name = function(name)
+      local hl = vim.api.nvim_get_hl(0, { name = name, link = false })
+      return { fg = hl.fg, bg = hl.bg, ctermfg = hl.ctermfg, ctermbg = hl.ctermbg }
+    end
+  else
+    get_hl_by_name = function(name)
+      ---@diagnostic disable-next-line undefined-field
+      local hlrgb = vim.api.nvim_get_hl_by_name(name, true)
+      ---@diagnostic disable-next-line undefined-field
+      local hl = vim.api.nvim_get_hl_by_name(name, false)
+      return {
+        fg = hlrgb.foreground,
+        bg = hlrgb.background,
+        ctermfg = hl.foreground,
+        ctermbg = hl.background,
+      }
+    end
+  end
+
   -- Setup the OutlineCurrent highlight group if it hasn't been done already by
   -- a theme or manually set
   if vim.fn.hlexists('OutlineCurrent') == 0 then
diff --git a/lua/outline/init.lua b/lua/outline/init.lua
index 43b3832..bd1f4f6 100644
--- a/lua/outline/init.lua
+++ b/lua/outline/init.lua
@@ -337,7 +337,7 @@ function M.setup(opts)
   }
 
   cfg.setup(opts)
-  highlight.setup_highlights()
+  highlight.setup()
 
   setup_global_autocmd()
   setup_commands()
diff --git a/lua/outline/parser.lua b/lua/outline/parser.lua
index 466e77d..b24b9de 100644
--- a/lua/outline/parser.lua
+++ b/lua/outline/parser.lua
@@ -1,8 +1,8 @@
 local cfg = require('outline.config')
 local folding = require('outline.folding')
-local lsp_utils = require('outline.utils.lsp_utils')
+local lsp_utils = require('outline.utils.lsp')
 local symbols = require('outline.symbols')
-local t_utils = require('outline.utils.table')
+local utils = require('outline.utils.init')
 
 local M = {}
 
@@ -56,7 +56,7 @@ local function parse_result(result, depth, hierarchy, parent, bufnr)
       local children = nil
       if value.children ~= nil then
         -- copy by value because we dont want it messing with the hir table
-        local child_hir = t_utils.array_copy(hir)
+        local child_hir = utils.array_copy(hir)
         table.insert(child_hir, isLast)
         children = parse_result(value.children, level + 1, child_hir, node, bufnr)
       else
@@ -123,4 +123,66 @@ function M.preorder_iter(items, children_check)
   end
 end
 
+---Merges a symbol tree recursively, only replacing nodes
+---which have changed. This will maintain the folding
+---status of any unchanged nodes.
+---@param new_node table New node
+---@param old_node table Old node
+---@param index? number Index of old_item in parent
+---@param parent? table Parent of old_item
+function M.merge_items_rec(new_node, old_node, index, parent)
+  local failed = false
+
+  if not new_node or not old_node then
+    failed = true
+  else
+    for key, _ in pairs(new_node) do
+      if
+        vim.tbl_contains({
+          'parent',
+          'children',
+          'folded',
+          'hovered',
+          'line_in_outline',
+          'hierarchy',
+        }, key)
+      then
+        goto continue
+      end
+
+      if key == 'name' then
+        -- in the case of a rename, just rename the existing node
+        old_node['name'] = new_node['name']
+      else
+        if not vim.deep_equal(new_node[key], old_node[key]) then
+          failed = true
+          break
+        end
+      end
+
+      ::continue::
+    end
+  end
+
+  if failed then
+    if parent and index then
+      parent[index] = new_node
+    end
+  else
+    local next_new_item = new_node.children or {}
+
+    -- in case new children are created on a node which
+    -- previously had no children
+    if #next_new_item > 0 and not old_node.children then
+      old_node.children = {}
+    end
+
+    local next_old_item = old_node.children or {}
+
+    for i = 1, math.max(#next_new_item, #next_old_item) do
+      M.merge_items_rec(next_new_item[i], next_old_item[i], i, next_old_item)
+    end
+  end
+end
+
 return M
diff --git a/lua/outline/providers/nvim-lsp.lua b/lua/outline/providers/nvim-lsp.lua
index bb33559..dec9f5a 100644
--- a/lua/outline/providers/nvim-lsp.lua
+++ b/lua/outline/providers/nvim-lsp.lua
@@ -1,6 +1,6 @@
 local config = require('outline.config')
 local jsx = require('outline.providers.jsx')
-local lsp_utils = require('outline.utils.lsp_utils')
+local lsp_utils = require('outline.utils.lsp')
 
 local M = {
   name = 'lsp',
diff --git a/lua/outline/sidebar.lua b/lua/outline/sidebar.lua
index 576ff10..7c49fd4 100644
--- a/lua/outline/sidebar.lua
+++ b/lua/outline/sidebar.lua
@@ -4,9 +4,7 @@ local folding = require('outline.folding')
 local parser = require('outline.parser')
 local providers = require('outline.providers.init')
 local utils = require('outline.utils.init')
-local writer = require('outline.writer')
 local symbols = require('outline.symbols')
-local t_utils = require('outline.utils.table')
 
 local strlen = vim.fn.strlen
 
@@ -105,25 +103,30 @@ function Sidebar:initial_handler(response, opts)
   end
 end
 
+-- stylua: ignore start
 ---Convenience function for setup_keymaps
 ---@param cfg_name string Field in cfg.o.keymaps
 ---@param method string|function If string, field in Sidebar
 ---@param args table Passed to method
 function Sidebar:nmap(cfg_name, method, args)
+  local keys = cfg.o.keymaps[cfg_name]
+  local fn
+
   if type(method) == 'string' then
-    utils.nmap(self.view.bufnr, cfg.o.keymaps[cfg_name], function()
-      Sidebar[method](self, unpack(args))
-    end)
+    fn = function() Sidebar[method](self, unpack(args)) end
   else
-    utils.nmap(self.view.bufnr, cfg.o.keymaps[cfg_name], function()
-      method(unpack(args))
-    end)
+    fn = function() method(unpack(args)) end
+  end
+
+  for _, key in ipairs(keys) do
+    vim.keymap.set( 'n', key, fn,
+      { silent = true, noremap = true, buffer = self.view.bufnr }
+    )
   end
 end
 
 function Sidebar:setup_keymaps()
   for name, meth in pairs({
-    -- stylua: ignore start
     goto_location = { '_goto_location', { true } },
     peek_location = { '_goto_location', { false } },
     restore_location = { '_map_follow_cursor', {} },
@@ -143,12 +146,12 @@ function Sidebar:setup_keymaps()
     fold_all = { '_set_all_folded', { true } },
     unfold_all = { '_set_all_folded', { false } },
     fold_reset = { '_set_all_folded', {} },
-    -- stylua: ignore end
   }) do
     ---@diagnostic disable-next-line param-type-mismatch
     self:nmap(name, meth[1], meth[2])
   end
 end
+-- stylua: ignore end
 
 ---Autocmds for the (current) outline buffer
 function Sidebar:setup_buffer_autocmd()
@@ -257,12 +260,12 @@ function Sidebar:update_cursor_pos(current)
   end
 end
 
----Calls writer.make_outline and then calls M.update_cursor_pos if
--- update_cursor is not false
+---Calls build_outline and then calls update_cursor_pos if update_cursor is
+--not false
 ---@param update_cursor boolean?
 ---@param set_cursor_to_node outline.SymbolNode|outline.FlatSymbolNode?
 function Sidebar:_update_lines(update_cursor, set_cursor_to_node)
-  local current = self:write_outline(set_cursor_to_node)
+  local current = self:build_outline(set_cursor_to_node)
   if update_cursor ~= false then
     self:update_cursor_pos(current)
   end
@@ -299,7 +302,7 @@ end
 
 ---@param items outline.SymbolNode[]
 function Sidebar:_merge_items(items)
-  utils.merge_items_rec({ children = items }, { children = self.items })
+  parser.merge_items_rec({ children = items }, { children = self.items })
 end
 
 ---Re-request symbols from provider
@@ -600,60 +603,57 @@ function Sidebar:_highlight_current_item(winnr, update_cursor)
 end
 
 ---The quintessential function of this entire plugin. Clears virtual text,
--- parses each node and replaces old lines with new lines to be written for the
--- outline buffer.
---
--- Handles highlights, virtual text, and of course lines of outline to write.
----@note Ensure new outlines are already set to `self.items` before calling this function. `self.flats` will be overwritten and current line is obtained from `win_get_cursor` using `self.code.win`.
+---parses each node and replaces old lines with new lines to be written for the
+---outline buffer.
+---
+---Handles highlights, virtual text, and of course lines of outline to write.
+---@note Ensure new outlines are already set to `self.items` before calling
+---this function. `self.flats` will be overwritten and current line is obtained
+---from `win_get_cursor` using `self.code.win`.
 ---@param find_node outline.FlatSymbolNode|outline.SymbolNode? Find a given node rather than node matching cursor position in codewin
 ---@return outline.FlatSymbolNode? set_cursor_to_this_node
-function Sidebar:write_outline(find_node)
-  -- 0-indexed
+function Sidebar:build_outline(find_node)
+  ---@type integer 0-indexed
   local hovered_line = vim.api.nvim_win_get_cursor(self.code.win)[1] - 1
-  -- Deepest matching node to put cursor on based on hovered line
-  local put_cursor    ---@type outline.FlatSymbolNode
-
+  ---@type outline.FlatSymbolNode Deepest visible matching node to set cursor
+  local put_cursor
   self.flats = {}
   local line_count = 0
-
   local lines = {}    ---@type string[]
   local details = {}  ---@type string[]
   local linenos = {}  ---@type string[]
-  local hl = {}
-
-  -- Find the prefix for each line needed for the lineno space
+  local hl = {}       ---@type outline.HL[]
+
+  -- Find the prefix for each line needed for the lineno space.
+  -- Use [max width of [max_line-1]] + 1 space padding.
+  -- -1 because if max_width is a power of ten, don't shift the entire lineno
+  -- column by the right just because the last line number requires an extra
+  -- digit. i.e.: If max_width is 1000, the lineno column will take up 3
+  -- columns to fill the digits, and 1 padding on the right. The 1000 can fit
+  -- perfectly there.
   local lineno_offset = 0
   local lineno_prefix = ''
   local lineno_max_width = #tostring(vim.api.nvim_buf_line_count(self.code.buf) - 1)
   if cfg.o.outline_items.show_symbol_lineno then
-    -- Use max width-1 plus 1 space padding.
-    -- -1 because if max_width is a power of ten, don't shift the entire lineno
-    -- column by the right just because the last line number requires an extra
-    -- digit. If max_width is 1000, the lineno column will take up 3 columns to
-    -- fill the digits, and 1 padding on the right. The 1000 can fit perfectly
-    -- there.
     lineno_offset = math.max(2, lineno_max_width) + 1
     lineno_prefix = string.rep(' ', lineno_offset)
   end
 
   -- Closures for convenience
-  local function add_guide_hl(from, to)
+  -- stylua: ignore start
+  local function save_guide_hl(from, to)
     table.insert(hl, {
-      line_count,
-      from,
-      to,
-      'OutlineGuides',
+      line = line_count, name = 'OutlineGuides',
+      from = from, to = to,
     })
   end
-
-  local function add_fold_hl(from, to)
+  local function save_fold_hl(from, to)
     table.insert(hl, {
-      line_count,
-      from,
-      to,
-      'OutlineFoldMarker',
+      line = line_count, name = 'OutlineFoldMarker',
+      from = from, to = to,
     })
   end
+  -- stylua: ignore end
 
   local guide_markers = cfg.o.guides.markers
   local fold_markers = cfg.o.symbol_folding.markers
@@ -687,7 +687,7 @@ function Sidebar:write_outline(find_node)
     table.insert(linenos, leftpad .. lineno)
 
     -- Make the guides for the line prefix
-    local pref = t_utils.str_to_table(string.rep(' ', node.depth))
+    local pref = utils.str_to_table(string.rep(' ', node.depth))
     local fold_marker_width = 0
 
     if folding.is_foldable(node) then
@@ -722,16 +722,15 @@ function Sidebar:write_outline(find_node)
       end
     end
 
-    -- Finished with guide prefix
-    -- Join all prefix chars by a space
+    -- Finished with guide prefix. Now join all prefix chars by a space
     local pref_str = table.concat(pref, ' ')
     local total_pref_len = lineno_offset + #pref_str
 
     -- Guide hl goes from start of prefix till before the fold marker, if any.
     -- Fold hl goes from start of fold marker until before the icon.
-    add_guide_hl(lineno_offset, total_pref_len - fold_marker_width)
+    save_guide_hl(lineno_offset, total_pref_len - fold_marker_width)
     if fold_marker_width > 0 then
-      add_fold_hl(total_pref_len - fold_marker_width, total_pref_len + 1)
+      save_fold_hl(total_pref_len - fold_marker_width, total_pref_len + 1)
     end
 
     local line = lineno_prefix .. pref_str
@@ -742,42 +741,35 @@ function Sidebar:write_outline(find_node)
     end
     line = line .. ' ' .. node.name
 
-    -- Highlight for the icon ✨
-    -- Start from icon col
+    -- Start from left of icon col
     local hl_start = #pref_str + #lineno_prefix + icon_pref
     local hl_end = hl_start + #node.icon -- until after icon
     local hl_type = cfg.o.symbols.icons[symbols.kinds[node.kind]].hl
-    table.insert(hl, { line_count, hl_start, hl_end, hl_type })
-
+    -- stylua: ignore start
+    table.insert(hl, {
+      line = line_count, name = hl_type,
+      from = hl_start, to = hl_end,
+    })
+    -- stylua: ignore end
     -- Prefix length is from start until the beginning of the node.name, used
     -- for hover highlights.
     node.prefix_length = hl_end + 1
 
-    -- lines passed to nvim_buf_set_lines cannot contain newlines in each line
+    -- Each line passed to nvim_buf_set_lines cannot contain newlines
     line = line:gsub('\n', ' ')
     table.insert(lines, line)
   end
 
-  -- Render
-
-  writer.clear_virt_text(self.view.bufnr)
-  writer.clear_icon_hl(self.view.bufnr)
-
-  vim.api.nvim_buf_set_option(self.view.bufnr, 'modifiable', true)
-  vim.api.nvim_buf_set_lines(self.view.bufnr, 0, -1, false, lines)
-  vim.api.nvim_buf_set_option(self.view.bufnr, 'modifiable', false)
-
-  -- Unfortunately highlights and extmarks cannot be added to lines that do not
-  -- yet exist. Hence these require another O(n) of iteration.
-  writer.add_highlights(self.view.bufnr, hl, self.flats)
-
-  if cfg.o.outline_items.show_symbol_details then
-    writer.add_details(self.view.bufnr, details)
-  end
-
-  if cfg.o.outline_items.show_symbol_lineno then
-    writer.add_linenos(self.view.bufnr, linenos)
-  end
+  -- PERF:
+  -- * Is setting individual lines is not as good as rewriting entire buffer?
+  --   That way we can set all highlights and virtual text together without
+  --   requiring extra O(n) iterations.
+  -- * Is there a significant difference if new lines are set first, on top
+  --   of old highlights, before resetting the highlights? (Rather than doing
+  --   like below)
+  self.view:clear_all_ns()
+  self.view:rewrite_lines(lines)
+  self.view:add_hl_and_ns(hl, self.flats, details, linenos)
 
   return put_cursor
 end
diff --git a/lua/outline/types/outline.lua b/lua/outline/types/outline.lua
index 9243ca1..484c8a9 100644
--- a/lua/outline/types/outline.lua
+++ b/lua/outline/types/outline.lua
@@ -74,7 +74,7 @@
 -- HELP
 
 ---@class outline.HL
----@field line integer
+---@field line integer Line number 1-indexed
 ---@field from integer
 ---@field to integer
 ---@field name string
diff --git a/lua/outline/utils/init.lua b/lua/outline/utils/init.lua
index f58666a..05ce12f 100644
--- a/lua/outline/utils/init.lua
+++ b/lua/outline/utils/init.lua
@@ -1,13 +1,9 @@
 local M = {}
 
 ---maps the table|string of keys to the action
----@param keys table|string
+---@param keys table
 ---@param action function|string
 function M.nmap(bufnr, keys, action)
-  if type(keys) == 'string' then
-    keys = { keys }
-  end
-
   for _, lhs in ipairs(keys) do
     vim.keymap.set('n', lhs, action, { silent = true, noremap = true, buffer = bufnr })
   end
@@ -33,78 +29,6 @@ function M.debounce(f, delay)
   end
 end
 
-function M.items_dfs(callback, children)
-  for _, val in ipairs(children) do
-    callback(val)
-
-    if val.children then
-      M.items_dfs(callback, val.children)
-    end
-  end
-end
-
----Merges a symbol tree recursively, only replacing nodes
----which have changed. This will maintain the folding
----status of any unchanged nodes.
----@param new_node table New node
----@param old_node table Old node
----@param index? number Index of old_item in parent
----@param parent? table Parent of old_item
-function M.merge_items_rec(new_node, old_node, index, parent)
-  local failed = false
-
-  if not new_node or not old_node then
-    failed = true
-  else
-    for key, _ in pairs(new_node) do
-      if
-        vim.tbl_contains({
-          'parent',
-          'children',
-          'folded',
-          'hovered',
-          'line_in_outline',
-          'hierarchy',
-        }, key)
-      then
-        goto continue
-      end
-
-      if key == 'name' then
-        -- in the case of a rename, just rename the existing node
-        old_node['name'] = new_node['name']
-      else
-        if not vim.deep_equal(new_node[key], old_node[key]) then
-          failed = true
-          break
-        end
-      end
-
-      ::continue::
-    end
-  end
-
-  if failed then
-    if parent and index then
-      parent[index] = new_node
-    end
-  else
-    local next_new_item = new_node.children or {}
-
-    -- in case new children are created on a node which
-    -- previously had no children
-    if #next_new_item > 0 and not old_node.children then
-      old_node.children = {}
-    end
-
-    local next_old_item = old_node.children or {}
-
-    for i = 1, math.max(#next_new_item, #next_old_item) do
-      M.merge_items_rec(next_new_item[i], next_old_item[i], i, next_old_item)
-    end
-  end
-end
-
 function M.flash_highlight(winnr, lnum, durationMs, hl_group)
   if durationMs == false then
     return
@@ -147,4 +71,49 @@ function M.str_or_nonempty_table(t)
   return type(t) == 'string' or M.table_has_content(t)
 end
 
+function M.table_to_str(t)
+  local ret = ''
+  for _, value in ipairs(t) do
+    ret = ret .. tostring(value)
+  end
+  return ret
+end
+
+function M.str_to_table(str)
+  local t = {}
+  for i = 1, #str do
+    t[i] = str:sub(i, i)
+  end
+  return t
+end
+
+--- Copies an array and returns it because lua usually does references
+---@generic T
+---@param t T[]
+---@return T[]
+function M.array_copy(t)
+  local ret = {}
+  for _, value in ipairs(t) do
+    table.insert(ret, value)
+  end
+  return ret
+end
+
+--- Deep copy a table, deeply excluding certain keys
+function M.deepcopy_excluding(t, keys)
+  local res = {}
+
+  for key, value in pairs(t) do
+    if not vim.tbl_contains(keys, key) then
+      if type(value) == 'table' then
+        res[key] = M.deepcopy_excluding(value, keys)
+      else
+        res[key] = value
+      end
+    end
+  end
+
+  return res
+end
+
 return M
diff --git a/lua/outline/utils/lsp_utils.lua b/lua/outline/utils/lsp.lua
similarity index 100%
rename from lua/outline/utils/lsp_utils.lua
rename to lua/outline/utils/lsp.lua
diff --git a/lua/outline/utils/table.lua b/lua/outline/utils/table.lua
deleted file mode 100644
index c692fc3..0000000
--- a/lua/outline/utils/table.lua
+++ /dev/null
@@ -1,48 +0,0 @@
-local M = {}
-
-function M.table_to_str(t)
-  local ret = ''
-  for _, value in ipairs(t) do
-    ret = ret .. tostring(value)
-  end
-  return ret
-end
-
-function M.str_to_table(str)
-  local t = {}
-  for i = 1, #str do
-    t[i] = str:sub(i, i)
-  end
-  return t
-end
-
---- Copies an array and returns it because lua usually does references
----@generic T
----@param t T[]
----@return T[]
-function M.array_copy(t)
-  local ret = {}
-  for _, value in ipairs(t) do
-    table.insert(ret, value)
-  end
-  return ret
-end
-
---- Deep copy a table, deeply excluding certain keys
-function M.deepcopy_excluding(t, keys)
-  local res = {}
-
-  for key, value in pairs(t) do
-    if not vim.tbl_contains(keys, key) then
-      if type(value) == 'table' then
-        res[key] = M.deepcopy_excluding(value, keys)
-      else
-        res[key] = value
-      end
-    end
-  end
-
-  return res
-end
-
-return M
diff --git a/lua/outline/view.lua b/lua/outline/view.lua
index b170d2b..6ab9aaf 100644
--- a/lua/outline/view.lua
+++ b/lua/outline/view.lua
@@ -1,4 +1,5 @@
 local cfg = require('outline.config')
+local highlight = require('outline.highlight')
 
 ---@class outline.View
 local View = {}
@@ -66,6 +67,7 @@ function View:setup_view(split_command)
   end
 end
 
+---Close view window and remove winnr/bufnr fields
 function View:close()
   if self.winnr then
     vim.api.nvim_win_close(self.winnr, true)
@@ -74,6 +76,7 @@ function View:close()
   end
 end
 
+---Return whether view has valid buf and win numbers
 function View:is_open()
   return self.winnr
     and self.bufnr
@@ -81,4 +84,45 @@ function View:is_open()
     and vim.api.nvim_win_is_valid(self.winnr)
 end
 
+---Replace all lines in buffer with given new `lines`
+---@param lines string[]
+function View:rewrite_lines(lines)
+  vim.api.nvim_buf_set_option(self.bufnr, 'modifiable', true)
+  vim.api.nvim_buf_set_lines(self.bufnr, 0, -1, false, lines)
+  vim.api.nvim_buf_set_option(self.bufnr, 'modifiable', false)
+end
+
+function View:clear_all_ns()
+  highlight.clear_all_ns(self.bufnr)
+end
+
+---Ensure all existing highlights are already cleared before calling!
+---@param hl outline.HL[]
+---@param nodes outline.FlatSymbolNode[]
+---@param details string[]
+---@param linenos string[]
+function View:add_hl_and_ns(hl, nodes, details, linenos)
+  highlight.items(self.bufnr, hl)
+  if cfg.o.outline_items.highlight_hovered_item then
+    highlight.hovers(self.bufnr, nodes)
+  end
+  if cfg.o.outline_items.show_symbol_details then
+    highlight.details(self.bufnr, details)
+  end
+
+  -- Note on hl_mode:
+  -- When hide_cursor + cursorline enabled, we want the lineno to also take on
+  -- the cursorline background so wherever the cursor is, it appears blended.
+  -- We want 'replace' even for `hide_cursor=false cursorline=true` because
+  -- vim's native line numbers do not get highlighted by cursorline.
+  if cfg.o.outline_items.show_symbol_lineno then
+    -- stylua: ignore start
+    highlight.linenos(
+      self.bufnr, linenos,
+      (cfg.o.outline_window.hide_cursor and 'combine') or 'replace'
+    )
+    -- stylua: ignore end
+  end
+end
+
 return View
diff --git a/lua/outline/writer.lua b/lua/outline/writer.lua
deleted file mode 100644
index e814fac..0000000
--- a/lua/outline/writer.lua
+++ /dev/null
@@ -1,89 +0,0 @@
-local cfg = require('outline.config')
-local highlight = require('outline.highlight')
-
-local M = {}
-
-local hlns = vim.api.nvim_create_namespace('outline-icon-highlight')
-local vtns = vim.api.nvim_create_namespace('outline-virt-text')
-
----@param bufnr integer
----@return boolean
-function M.is_buffer_outline(bufnr)
-  if not vim.api.nvim_buf_is_valid(bufnr) then
-    return false
-  end
-  local name = vim.api.nvim_buf_get_name(bufnr)
-  local ft = vim.api.nvim_buf_get_option(bufnr, 'filetype')
-  return string.match(name, 'OUTLINE') ~= nil and ft == 'Outline'
-end
-
----Apply highlights and hover highlights to bufnr
----@param bufnr integer
----@param nodes outline.FlatSymbolNode[] flattened nodes
-function M.add_highlights(bufnr, hl_info, nodes)
-  for _, line_hl in ipairs(hl_info) do
-    local line, hl_start, hl_end, hl_type = unpack(line_hl)
-    vim.api.nvim_buf_add_highlight(bufnr, hlns, hl_type, line - 1, hl_start, hl_end)
-  end
-  M.add_hover_highlights(bufnr, nodes)
-end
-
----@param bufnr integer Outline buffer
-function M.clear_icon_hl(bufnr)
-  vim.api.nvim_buf_clear_namespace(bufnr, hlns, 0, -1)
-end
-
----@param bufnr integer Outline buffer
-function M.clear_virt_text(bufnr)
-  vim.api.nvim_buf_clear_namespace(bufnr, vtns, 0, -1)
-end
-
----@param bufnr integer Outline buffer
----@param nodes outline.FlatSymbolNode[]
-function M.add_hover_highlights(bufnr, nodes)
-  if not cfg.o.outline_items.highlight_hovered_item then
-    return
-  end
-
-  -- clear old highlight
-  highlight.clear_hover_highlight(bufnr)
-  for _, node in ipairs(nodes) do
-    if node.hovered then
-      highlight.add_hover_highlight(bufnr, node.line_in_outline - 1, node.prefix_length)
-    end
-  end
-end
-
----@param bufnr integer Outline buffer
----@param details string[]
-function M.add_details(bufnr, details)
-  for index, value in ipairs(details) do
-    vim.api.nvim_buf_set_extmark(bufnr, vtns, index - 1, -1, {
-      virt_text = { { value, 'OutlineDetails' } },
-      virt_text_pos = 'eol',
-      hl_mode = 'combine',
-    })
-  end
-end
-
----@param bufnr integer Outline buffer
----@param linenos string[] Must already be padded
-function M.add_linenos(bufnr, linenos)
-  -- TODO: Fix lineno not appearing if text in line is truncated on the right
-  -- due to narrow window, after nvim fixes virt_text_hide.
-  for index, value in ipairs(linenos) do
-    vim.api.nvim_buf_set_extmark(bufnr, vtns, index - 1, -1, {
-      virt_text = { { value, 'OutlineLineno' } },
-      virt_text_pos = 'overlay',
-      virt_text_win_col = 0,
-      -- When hide_cursor + cursorline enabled, we want the lineno to also
-      -- take on the cursorline background so wherever the cursor is, it
-      -- appears blended. We want 'replace' even for `hide_cursor=false
-      -- cursorline=true` because vim's native line numbers do not get
-      -- highlighted by cursorline.
-      hl_mode = (cfg.o.outline_window.hide_cursor and 'combine') or 'replace',
-    })
-  end
-end
-
-return M