feat: color filetype icons when using nvim-devicons (#222)

README.md

@@ -304,6 +304,12 @@ file_status | true | Displays file status (readonly status, modified status)
 path | 0 | filename `path` option: 0 = just filename, 1 = relative path, 2 = absolute path
 symbols | `{modified = '[+]', readonly = '[-]'}` | changes status symbols | table containing one or more symbols |
 
+* `filetype` component options
+
+Option   | Default | Behaviour
+:------: | :------: | :----:
+colored | true | Displays filetype icon in color if set to `true`
+
 * `diff` component options
 
 Option   | Default | Behaviour | Format

doc/lualine.txt

@@ -412,6 +412,10 @@ In addition, some components have unique options.
     • symbols (`{modified = '[+]', readonly = '[-]'}`)
       changes status symbols
 
+  • filetype~
+    • colored  (true)
+      Displays filetype icon in color if set to `true`
+
   • fileformat~
     • icons_enabled (true)
       Whether to displays icon before component. Colors

lua/lualine/components/filetype.lua

@@ -1,5 +1,8 @@
 -- Copyright (c) 2020-2021 hoob3rt
 -- MIT license, see LICENSE for more details.
+local highlight = require('lualine.highlight')
+local utils = require('lualine.utils.utils')
+
 local FileType = require('lualine.component'):new()
 
 FileType.update_status = function(self)
@@ -8,7 +11,30 @@ FileType.update_status = function(self)
     local ok, devicons = pcall(require, 'nvim-web-devicons')
     if ok then
       local f_name, f_extension = vim.fn.expand('%:t'), vim.fn.expand('%:e')
-      self.options.icon = devicons.get_icon(f_name, f_extension)
+      local icon, icon_highlight_group = devicons.get_icon(f_name, f_extension)
+      self.options.icon = icon
+
+      if self.options.icon and
+          (self.options.colored or self.options.colored == nil) then
+        self.options.colored = true
+
+        local highlight_color = utils.extract_highlight_colors(icon_highlight_group, 'fg')
+        local is_focused = vim.g.statusline_winid == vim.fn.win_getid()
+        local default_highlight = highlight.format_highlight(is_focused,
+                                                             self.options.self
+                                                                 .section)
+        local icon_highlight = self.options.self.section .. '_' ..
+                                   icon_highlight_group
+        if not utils.highlight_exists(icon_highlight .. '_normal') then
+          icon_highlight = highlight.create_component_highlight_group(
+                               {fg = highlight_color}, icon_highlight_group,
+                               self.options)
+        end
+
+        self.options.icon =
+            highlight.component_format_highlight(icon_highlight) ..
+                self.options.icon .. default_highlight
+      end
     else
       ok = vim.fn.exists('*WebDevIconsGetFileTypeSymbol')
       if ok ~= 0 then

lua/tests/spec/component_spec.lua

@@ -241,6 +241,55 @@ describe('Fileformat component', function()
   end)
 end)
 
+describe('Filetype component', function()
+  local filetype
+
+  before_each(function()
+    filetype = vim.bo.filetype
+    vim.bo.filetype = 'lua'
+  end)
+
+  after_each(function()
+    vim.bo.filetype = filetype
+  end)
+
+  it('does not add icon when library unavailable', function()
+    local opts = build_component_opts({
+      component_separators = {'', ''},
+      padding = 0
+    })
+    assert_component('filetype', opts, 'lua')
+  end)
+
+  it('colors nvim-web-devicons icons', function()
+    package.loaded['nvim-web-devicons'] = {
+      get_icon = function()
+        return '*', 'test_highlight_group'
+      end
+    }
+
+    local hl = require 'lualine.highlight'
+    local utils = require 'lualine.utils.utils'
+    stub(hl, 'create_component_highlight_group')
+    stub(utils, 'extract_highlight_colors')
+    hl.create_component_highlight_group.returns('MyCompHl')
+    utils.extract_highlight_colors.returns('#000')
+
+    local opts = build_component_opts({
+      component_separators = {'', ''},
+      padding = 0
+    })
+    assert_component('filetype', opts, '%#MyCompHl_normal#*%#lualine_c_normal# lua')
+    assert.stub(utils.extract_highlight_colors).was_called_with('test_highlight_group', 'fg')
+    opts.icon = '*'
+    assert.stub(hl.create_component_highlight_group).was_called_with(
+      {fg = '#000'}, 'test_highlight_group', opts
+    )
+    hl.create_component_highlight_group:revert()
+    utils.extract_highlight_colors:revert()
+  end)
+end)
+
 describe('Hostname component', function()
   it('works', function()
     stub(vim.loop, 'os_gethostname')