Emacs Dart IDE using lsp-mode to connect to Dart Analysis Server.

LSP works great with Flutter, but there are also other packages that may help to improve your development, for more info see Additional packages.

The following has a example to setup lsp-dart.

(require 'package)
(add-to-list 'package-archives '("melpa" . "http://melpa.org/packages/") t)
(package-initialize)

(setq package-selected-packages 
  '(dart-mode lsp-mode lsp-dart lsp-treemacs flycheck company
    ;; Optional packages
    lsp-ui company hover))

(when (cl-find-if-not #'package-installed-p package-selected-packages)
  (package-refresh-contents)
  (mapc #'package-install package-selected-packages))

(add-hook 'dart-mode-hook 'lsp)

(setq gc-cons-threshold (* 100 1024 1024)
      read-process-output-max (* 1024 1024))

Besides the lsp-mode features, lsp-dart implements the custom methods features from the dart_analysis_server.

lsp-dart uses lsp-treemacs for rendering some tree views features.

lsp-dart-show-outline ⚠️*

lsp-dart-show-flutter-outline ⚠️*

lsp-dart-run-all-tests - Run all tests from project.

lsp-dart-run-test-file - Run all tests from current test buffer.

lsp-dart-run-test-at-point - Run single test at point.

lsp-dart-debug-test-at-point - Debug single test at point.

lsp-dart-visit-last-test - Go to last ran test.

lsp-dart-run-last-test - Run last ran test.

lsp-dart-debug-last-test - Debug last ran test.

Running a test interactively:

lsp-dart-test-show-tree - Open the test tree containing the latest ran tests.

For more options, check the settings section.

Display the flutter colors on left fringe.

You can disable the feature setting lsp-dart-flutter-fringe-colors to nil.

Display widget guide lines from parent to child widgets on flutter. ⚠️*

You can disable the feature setting lsp-dart-flutter-widget-guides to nil.

To run your app you can use lsp-dart-run which will use dap-mode but for running without debug. to pass custom arguments it's possible to pass a prefix-argument with arguments separated by space.

For debugging, lsp-dart uses dap-mode. You only need to run lsp-dart-dap-setup one time to setup the debugger to your Emacs and dap-debug to start the debug.

lsp-dart support Flutter debugging too via dap-debug with an option to select the device to debug.

After the debug session has started, you can run:

lsp-dart-flutter-hot-restart - Trigger Flutter hot restart on the debug sessions.

lsp-dart-flutter-hot-reload - Trigger Flutter hot reload on the debug sessions.

For hot-reload/restart on buffer save you can enable lsp-dart-dap-flutter-hot-reload-on-save or lsp-dart-dap-flutter-hot-restart-on-save.

You can register a custom template for debugging with dap-register-debug-template, check the following example:

(use-package lsp-dart
  :ensure t
  :hook (dart-mode . lsp)
  :init
  (dap-register-debug-template "Flutter :: Custom debug"
                               (list :flutterPlatform "x86_64"
                                     :program "lib/main_debug.dart"
                                     :args '("--flavor" "customer_a"))))

flutterPlatform,:program, and :args are all optional.

A full list of supported parameters can be found in the source of the function lsp-dart-dap--populate-flutter-start-file-args in lsp-dart-dap.el. Several of these parameters can be configured by setting one of the Supported settings with matching names.

You can also open the Dart DevTools on the current debug session with lsp-dart-open-devtools.

lsp-dart supports running Flutter and Dart commands as following:

lsp-dart-pub-get - Run pub get or flutter pub get on project root.

lsp-dart-pub-upgrade - Run pub upgrade or flutter pub upgrade on project root.

lsp-dart-pub-outdated - Run pub outdated or flutter pub outdated on project root.

• lsp-ui : Flycheck, documentation and code actions support.
• lsp-treemacs : lsp-mode GUI controls implemented using treemacs.
• company-capf : Completion back-end support.
• hover.el : Tool to run flutter mobile apps from desktop without the need of an emulator.
• flutter.el : Tool to run flutter binary as an inferior process and interact with it from Emacs.

❔ Emacs can't find my package, it keeps searching up until the dart root package folder.

🔹 Configure projectile to find the package pubspec.yaml and set the folder as project root:

(with-eval-after-load 'projectile
  (add-to-list 'projectile-project-root-files-bottom-up "pubspec.yaml")
  (add-to-list 'projectile-project-root-files-bottom-up "BUILD"))

❔ LSP :: No LSP server for dart-mode(check *lsp-log*).

🔹 Try to set the lsp-dart-sdk-dir to the Dart SDK dir installation or if you are using Flutter, <your-flutter-dir>/bin/cache/dart-sdk/.

All feedback and suggestions are very welcome!

You can open a issue or for a quick answer, send a message on Gitter.