feat(outline): allow disabling or overriding outline icons

README.md

@@ -300,7 +300,8 @@ require("flutter-tools").setup {
   },
   outline = {
     open_cmd = "30vnew", -- command to use to open the outline buffer
-    auto_open = false -- if true this will open the outline automatically when it is first populated
+    auto_open = false, -- if true this will open the outline automatically when it is first populated
+    icons = true, -- false hides the icons (e.g. without a Nerd Font); a table overrides icons per kind, e.g. { CLASS = "C", DEFAULT = "*" }
   },
   lsp = {
     on_attach = my_custom_on_attach,

lua/flutter-tools/config.lua

@@ -47,7 +47,7 @@ local utils = lazy.require("flutter-tools.utils") ---@module "flutter-tools.util
 ---@field debugger? {enabled: boolean, exception_breakpoints?: table, evaluate_to_string_in_debug_views?: boolean, register_configurations?: fun(paths: table)}
 ---@field closing_tags? {highlight: string, prefix: string, priority: number, enabled: boolean}
 ---@field lsp? {debug?: number, color?: {enabled: boolean, background: boolean, foreground: boolean, virtual_text: boolean, virtual_text_str: string, background_color?: string}, settings?: table}
----@field outline? {auto_open: boolean, open_cmd?: string}
+---@field outline? {auto_open: boolean, open_cmd?: string, icons?: boolean|table<string, string>}
 ---@field dev_log? flutter.DevLogOpts
 ---@field dev_tools? {autostart: boolean, auto_open_browser: boolean}
 ---@field widget_preview? {web_server: boolean}
@@ -75,6 +75,9 @@ local function validate_prefs(prefs)
     )
   end
   vim.validate("outline", prefs.outline, "table", true)
+  if prefs.outline then
+    vim.validate("outline.icons", prefs.outline.icons, { "boolean", "table" }, true)
+  end
   vim.validate("dev_log", prefs.dev_log, "table", true)
   vim.validate("closing_tags", prefs.closing_tags, "table", true)
 end
@@ -142,6 +145,7 @@ local config = {
   },
   outline = setmetatable({
     auto_open = false,
+    icons = true,
   }, {
     __index = function(_, k) return k == "open_cmd" and get_split_cmd(0.3, 40) or nil end,
   }),

lua/flutter-tools/outline.lua

@@ -26,7 +26,7 @@ local markers = {
   horizontal = "─",
 }
 
-local icons = setmetatable({
+local default_icons = {
   TOP_LEVEL_VARIABLE = "",
   CLASS = "",
   FIELD = "󰐾",
@@ -38,27 +38,38 @@ local icons = setmetatable({
   ENUM = "󰉺",
   ENUM_CONSTANT = "",
   DEFAULT = "",
-}, {
-  __index = function(t, _) return t.DEFAULT end,
-})
+}
 
 local HL_PREFIX = "FlutterToolsOutline"
 local MARKER_HL = "FlutterToolsOutlineIndentGuides"
 
 local icon_highlights = {
-  [icons.TOP_LEVEL_VARIABLE] = { name = "TopLevelVar", link = "Identifier" },
-  [icons.CLASS] = { name = "Class", link = "Type" },
-  [icons.FIELD] = { name = "Field", link = "Identifier" },
-  [icons.CONSTRUCTOR] = { name = "Constructor", link = "Identifier" },
-  [icons.CONSTRUCTOR_INVOCATION] = { name = "ConstructorInvocation", link = "Special" },
-  [icons.FUNCTION] = { name = "Function", link = "Function" },
-  [icons.METHOD] = { name = "Method", link = "Function" },
-  [icons.GETTER] = { name = "Getter", link = "Function" },
-  [icons.ENUM] = { name = "Enum", link = "Type" },
-  [icons.ENUM_CONSTANT] = { name = "EnumConstant", link = "Type" },
-  [icons.DEFAULT] = { name = "Default", link = ui.DIM_HL },
+  TOP_LEVEL_VARIABLE = { name = "TopLevelVar", link = "Identifier" },
+  CLASS = { name = "Class", link = "Type" },
+  FIELD = { name = "Field", link = "Identifier" },
+  CONSTRUCTOR = { name = "Constructor", link = "Identifier" },
+  CONSTRUCTOR_INVOCATION = { name = "ConstructorInvocation", link = "Special" },
+  FUNCTION = { name = "Function", link = "Function" },
+  METHOD = { name = "Method", link = "Function" },
+  GETTER = { name = "Getter", link = "Function" },
+  ENUM = { name = "Enum", link = "Type" },
+  ENUM_CONSTANT = { name = "EnumConstant", link = "Type" },
+  DEFAULT = { name = "Default", link = ui.DIM_HL },
 }
 
+---@param kind string?
+---@return string? icon
+---@return string? highlight
+local function get_icon(kind)
+  local opts = config.outline.icons
+  if opts == false then return end
+  local overrides = type(opts) == "table" and opts or {}
+  kind = kind or "DEFAULT"
+  local icon = overrides[kind] or default_icons[kind] or overrides.DEFAULT or default_icons.DEFAULT
+  if icon == "" then return end
+  return icon, HL_PREFIX .. (icon_highlights[kind] or icon_highlights.DEFAULT).name
+end
+
 api.nvim_set_hl(0, MARKER_HL, { default = true, link = "NonText" })
 
 -----------------------------------------------------------------------------//
@@ -103,8 +114,8 @@ local function set_outline_highlights()
   for key, value in pairs(markers) do
     highlight_item(key:gsub("^%l", string.upper), value, MARKER_HL)
   end
-  for icon, hl in pairs(icon_highlights) do
-    highlight_item(hl.name, icon, hl.link)
+  for _, hl in pairs(icon_highlights) do
+    hl_link(hl.name, hl.link)
   end
 end
 
@@ -142,10 +153,11 @@ local function parse_outline(result, node, indent, marker)
   local range = node.codeRange
   local element = node.element or {}
   local text = {}
-  local icon = icons[element.kind]
-  local display_str = { indent, marker, icon }
-
+  local display_str = { indent, marker }
   local hl = {}
+
+  local icon, icon_hl = get_icon(element.kind)
+  if icon then add_segment(display_str, hl, icon, icon_hl, #table.concat(display_str, " ")) end
   local length = #table.concat(display_str, " ")
 
   local return_type = element.returnType and element.returnType .. " "

tests/outline_spec.lua

@@ -0,0 +1,58 @@
+describe("outline", function()
+  local config
+  local outline
+  local uri = "file:///tmp/main.dart"
+  local class_icon = "\xef\x83\xa8"
+  local method_icon = "\xf3\xb0\x86\xa7"
+
+  local function node(kind, name, children)
+    return {
+      element = { kind = kind, name = name },
+      codeRange = { start = { line = 0, character = 0 }, ["end"] = { line = 1, character = 0 } },
+      children = children,
+    }
+  end
+
+  local function render(outline_config)
+    config.set({ outline = outline_config })
+    outline.document_outline(nil, {
+      uri = uri,
+      outline = { children = { node("CLASS", "Foo", { node("METHOD", "bar") }) } },
+    })
+    return outline.outlines[uri]
+  end
+
+  before_each(function()
+    package.loaded["flutter-tools.config"] = nil
+    package.loaded["flutter-tools.outline"] = nil
+    config = require("flutter-tools.config")
+    outline = require("flutter-tools.outline")
+  end)
+
+  it("shows icons highlighted by kind by default", function()
+    local result = render(nil)
+    assert.are.same("  " .. class_icon .. " Foo", result[1].text)
+    assert.are.same({
+      value = class_icon,
+      highlight = "FlutterToolsOutlineClass",
+      column_start = 2,
+      column_end = 2 + #class_icon,
+    }, result[1].hl[1])
+    assert.are.same("FlutterToolsOutlineMethod", result[2].hl[1].highlight)
+  end)
+
+  it("hides icons and their highlights when disabled", function()
+    local result = render({ icons = false })
+    assert.are.same("  Foo", result[1].text)
+    assert.are.same("   └ bar", result[2].text)
+    assert.are.same("None", result[1].hl[1].highlight)
+    assert.are.same(2, result[1].hl[1].column_start)
+  end)
+
+  it("uses icon overrides and falls back to the defaults", function()
+    local result = render({ icons = { CLASS = "C" } })
+    assert.are.same("  C Foo", result[1].text)
+    assert.are.same(4, result[1].hl[2].column_start)
+    assert.are.same("   └ " .. method_icon .. " bar", result[2].text)
+  end)
+end)