add project_root_callback for tsserver (#2290)

* add project_root_callback for tsserver
* add tests for tsserver project root
* Update test/command_callback/test_javascript_tsserver_command_callback.vader

ale_linters/javascript/tsserver.vim

@@ -12,6 +12,6 @@ call ale#linter#Define('javascript', {
 \       'node_modules/.bin/tsserver',
 \   ]),
 \   'command': '%e',
-\   'project_root_callback': {-> ''},
+\   'project_root_callback': 'ale#handlers#tsserver#GetProjectRoot',
 \   'language': '',
 \})

ale_linters/typescript/tsserver.vim

@@ -12,6 +12,6 @@ call ale#linter#Define('typescript', {
 \       'node_modules/.bin/tsserver',
 \   ]),
 \   'command': '%e',
-\   'project_root_callback': {-> ''},
+\   'project_root_callback': 'ale#handlers#tsserver#GetProjectRoot',
 \   'language': '',
 \})

autoload/ale/handlers/tsserver.vim

@@ -0,0 +1,8 @@
+" Author: Derek Sifford <dereksifford@gmail.com>
+" Description: Handlers for tsserver
+
+function! ale#handlers#tsserver#GetProjectRoot(buffer) abort
+    let l:tsconfig_file = ale#path#FindNearestFile(a:buffer, 'tsconfig.json')
+
+    return !empty(l:tsconfig_file) ? fnamemodify(l:tsconfig_file, ':h') : ''
+endfunction

test/command_callback/test_javascript_tsserver_command_callback.vader

@@ -6,3 +6,11 @@ After:
 
 Execute(The default command should be correct):
   AssertLinter 'tsserver', ale#Escape('tsserver')
+
+Execute(should resolve correct path when nested 1):
+  call ale#test#SetFilename('tsserver_paths/src/level-1/level-2/file3.ts')
+  AssertLSPProject ale#path#Simplify(g:dir . '/tsserver_paths/src/level-1')
+
+Execute(should resolve correct path when nested 2):
+  call ale#test#SetFilename('tsserver_paths/src/file1.ts')
+  AssertLSPProject ale#path#Simplify(g:dir . '/tsserver_paths')