add jdelStrother's flow-type layer with some changes

layers/+lang/flow-type/README.org

@@ -0,0 +1,33 @@
+#+TITLE: flow-type layer
+
+* Description
+This layer adds some [[https://flowtype.org/][flow]] related functionality to Emacs:
+ - Show the flow-type of the object under the cursor using Eldoc
+ - Add flow checking to flycheck (based on the flycheck-flow package)
+ - company-mode completion using company-flow
+ - "compilation" using =flow status=
+
+* Install
+To use this configuration layer, add it to your =~/.spacemacs=. You will need to
+add =flow-type= to the existing =dotspacemacs-configuration-layers= list in this
+file. Please ensure you already have the flow binary installed, either in
+node_modules or in your PATH.
+
+The type under the cursor is shown automatically using eldoc.  You may find this
+a little sluggish, depending on your setup - if so, you can disable it by setting
+=flow-type-enable-eldoc-type-info= to =nil=.
+
+#+BEGIN_SRC emacs-lisp
+(flow-type :variables flow-type-enable-eldoc-type-info nil)
+#+END_SRC
+
+You can always show types manually using =flow-minor-type-at-pos=,
+bound to =,ft= by default.
+
+* flow-minor-mode key bindings
+  | ,fb | xref-pop-marker-stack         | jump back from definition                               |
+  | ,fc | flow-minor-status             | run `flow status' as a compiler                         |
+  | ,fd | flow-minor-jump-to-definition | jump to the definition of the variable under the cursor |
+  | ,ff | flow-minor-suggest            |                                                         |
+  | ,fo | flow-minor-coverage           | print coverage information                              |
+  | ,ft | flow-minor-type-at-pos        | print the type under the cursor to the message line     |

layers/+lang/flow-type/config.el

@@ -0,0 +1,14 @@
+;;; config.el --- flow-type layer configuration file for Spacemacs.
+;;
+;; Copyright (c) 2012-2018 Sylvain Benner & Contributors
+;;
+;; Author: Mike Holm <coldpour@gmail.com>
+;; URL: https://github.com/syl20bnr/spacemacs
+;;
+;; This file is not part of GNU Emacs.
+;;
+;;; License: GPLv3
+
+(defvar flow-type-enable-eldoc-type-info t
+  "When t, automatically display the type under the cursor using eldoc.
+When nil, types can be displayed manually with `flow-minor-type-at-pos'.")

layers/+lang/flow-type/funcs.el

@@ -0,0 +1,13 @@
+;;; funcs.el --- flow-type layer functions file for Spacemacs.
+;;
+;; Copyright (c) 2012-2018 Sylvain Benner & Contributors
+;;
+;; Author: Mike Holm <coldpour@gmail.com>
+;; URL: https://github.com/syl20bnr/spacemacs
+;;
+;; This file is not part of GNU Emacs.
+;;
+;;; License: GPLv3
+
+(defun flow-type-eldoc-hook ()
+  (set (make-local-variable 'eldoc-documentation-function) 'flow-minor-get-type-at-pos))

layers/+lang/flow-type/layers.el

@@ -0,0 +1,12 @@
+;;; layers.el --- flow-type Layer layers File for Spacemacs
+;;
+;; Copyright (c) 2012-2018 Sylvain Benner & Contributors
+;;
+;; Author: Holm <holmi09@holmi09mac132>
+;; URL: https://github.com/syl20bnr/spacemacs
+;;
+;; This file is not part of GNU Emacs.
+;;
+;;; License: GPLv3
+
+(configuration-layer/declare-layers '(node))

layers/+lang/flow-type/packages.el

@@ -0,0 +1,72 @@
+;;; packages.el --- flow-type layer packages file for Spacemacs.
+;;
+;; Copyright (c) 2012-2016 Sylvain Benner & Contributors
+;;
+;; Author: Mike Holm <coldpour@gmail.com>
+;; URL: https://github.com/syl20bnr/spacemacs
+;;
+;; This file is not part of GNU Emacs.
+;;
+;;; License: GPLv3
+
+(defconst flow-type-packages
+  '(
+    flow-minor-mode
+    company
+    (company-flow :toggle (configuration-layer/package-usedp 'company))
+    (flycheck-flow :toggle (configuration-layer/package-usedp 'flycheck))
+    eldoc
+    ))
+
+(defun flow-type/init-flow-minor-mode()
+  (use-package flow-minor-mode
+    :defer t
+    :init
+    (progn
+      (add-hook 'js2-mode-hook 'flow-minor-enable-automatically)
+      (add-hook 'react-mode-hook 'flow-minor-enable-automatically)
+      )
+    :config
+    (progn
+      ;; enable jumping with ,gg
+      (add-to-list 'spacemacs-jump-handlers-js2-mode 'flow-minor-jump-to-definition)
+      (add-to-list 'spacemacs-jump-handlers-react-mode 'flow-minor-jump-to-definition)
+
+      (spacemacs/declare-prefix-for-mode 'flow-minor-mode "mf" "flow" "flow type checker commands")
+      (spacemacs/set-leader-keys-for-minor-mode 'flow-minor-mode
+        "fb" 'xref-pop-marker-stack
+        "fd" 'flow-minor-jump-to-definition
+        "fc" 'flow-minor-status
+        "ff" 'flow-minor-suggest
+        "fo" 'flow-minor-coverage
+        "ft" 'flow-minor-type-at-pos
+        ))))
+
+(defun flow-type/post-init-eldoc()
+  (when flow-type-enable-eldoc-type-info
+    (add-hook 'js2-mode-hook 'flow-type-eldoc-hook)
+    (add-hook 'react-mode-hook 'flow-type-eldoc-hook)))
+
+(defun flow-type/post-init-company()
+  (spacemacs|add-company-backends :backends company-flow :modes js2-mode react-mode))
+
+(defun flow-type/init-company-flow ()
+  (use-package company-flow
+    :defer t
+    :config
+    (when (configuration-layer/layer-usedp 'react)
+      (push 'react-mode company-flow-modes))))
+
+(defun flow-type/init-flycheck-flow()
+  (with-eval-after-load 'flycheck
+    (use-package flycheck-flow
+      :config
+      (progn
+        ;; Don't run flow if there's no @flow pragma
+        (custom-set-variables '(flycheck-javascript-flow-args (quote ("--respect-pragma"))))
+        ;; Run flow in react-mode files
+        (flycheck-add-mode 'javascript-flow 'react-mode)
+        ;; After running js-flow, run js-eslint
+        ;; doing this in the other order causes a lot of repeated errors!!!
+        (flycheck-add-next-checker 'javascript-flow 'javascript-eslint)
+      ))))