Quietly add go to definition support for tsserver

test/lsp/test_lsp_client_messages.vader

@@ -177,3 +177,16 @@ Execute(ale#lsp#tsserver_message#CompletionEntryDetails() should return correct
   \   }
   \ ],
   \ ale#lsp#tsserver_message#CompletionEntryDetails(bufnr(''), 347, 12, ['foo', 'bar'])
+
+Execute(ale#lsp#tsserver_message#Definition() should return correct messages):
+  AssertEqual
+  \ [
+  \   0,
+  \   'ts@definition',
+  \   {
+  \     'file': ale#path#Winify(g:dir . '/foo/bar.ts'),
+  \     'line': 347,
+  \     'offset': 12,
+  \   }
+  \ ],
+  \ ale#lsp#tsserver_message#Definition(bufnr(''), 347, 12)

test/test_go_to_definition.vader

@@ -0,0 +1,138 @@
+Before:
+  call ale#test#SetDirectory('/testplugin/test')
+  call ale#test#SetFilename('dummy.txt')
+
+  let g:old_filename = expand('%:p')
+  let g:Callback = 0
+  let g:message = []
+  let g:expr_list = []
+
+  runtime autoload/ale/definition.vim
+  runtime autoload/ale/linter.vim
+  runtime autoload/ale/lsp.vim
+
+  function! ale#linter#StartLSP(buffer, linter, callback) abort
+    let g:Callback = a:callback
+
+    return {
+    \ 'connection_id': 347,
+    \ 'project_root': '/foo/bar',
+    \}
+  endfunction
+
+  function! ale#lsp#Send(conn_id, message, root) abort
+    let g:message = a:message
+
+    return 42
+  endfunction
+
+  function! ale#definition#Execute(expr) abort
+    call add(g:expr_list, a:expr)
+  endfunction
+
+After:
+  call ale#test#RestoreDirectory()
+  call ale#linter#Reset()
+
+  unlet! g:old_filename
+  unlet! g:Callback
+  unlet! g:message
+  unlet! g:expr_list
+
+  runtime autoload/ale/definition.vim
+  runtime autoload/ale/linter.vim
+  runtime autoload/ale/lsp.vim
+
+Execute(Other messages for the tsserver handler should be ignored):
+  call ale#definition#HandleTSServerResponse(1, {'command': 'foo'})
+
+Execute(Failed definition responses should be handled correctly):
+  call ale#definition#SetMap({3: {'open_in_tab': 0}})
+  call ale#definition#HandleTSServerResponse(
+  \ 1,
+  \ {'command': 'definition', 'request_seq': 3}
+  \)
+  AssertEqual {}, ale#definition#GetMap()
+
+Given typescript(Some typescript file):
+  foo
+  somelongerline
+  bazxyzxyzxyz
+
+Execute(Other files should be jumped to for definition responses):
+  call ale#definition#SetMap({3: {'open_in_tab': 0}})
+  call ale#definition#HandleTSServerResponse(
+  \ 1,
+  \ {
+  \   'command': 'definition',
+  \   'request_seq': 3,
+  \   'success': v:true,
+  \   'body': [
+  \     {
+  \       'file': g:dir . '/completion_dummy_file',
+  \       'start': {'line': 3, 'offset': 7},
+  \     },
+  \   ],
+  \ }
+  \)
+
+  AssertEqual
+  \ [
+  \   'edit ' . fnameescape(g:dir . '/completion_dummy_file'),
+  \ ],
+  \ g:expr_list
+  AssertEqual [3, 7], getpos('.')[1:2]
+  AssertEqual {}, ale#definition#GetMap()
+
+Execute(Other files should be jumped to for definition responses in tabs too):
+  call ale#definition#SetMap({3: {'open_in_tab': 1}})
+  call ale#definition#HandleTSServerResponse(
+  \ 1,
+  \ {
+  \   'command': 'definition',
+  \   'request_seq': 3,
+  \   'success': v:true,
+  \   'body': [
+  \     {
+  \       'file': g:dir . '/completion_dummy_file',
+  \       'start': {'line': 3, 'offset': 7},
+  \     },
+  \   ],
+  \ }
+  \)
+
+  AssertEqual
+  \ [
+  \   'tabedit ' . fnameescape(g:dir . '/completion_dummy_file'),
+  \ ],
+  \ g:expr_list
+  AssertEqual [3, 7], getpos('.')[1:2]
+  AssertEqual {}, ale#definition#GetMap()
+
+Execute(tsserver completion requests should be sent):
+  runtime ale_linters/typescript/tsserver.vim
+  call setpos('.', [bufnr(''), 2, 5, 0])
+
+  ALEGoToDefinition
+
+  AssertEqual
+  \ 'function(''ale#definition#HandleTSServerResponse'')',
+  \ string(g:Callback)
+  AssertEqual
+  \ [0, 'ts@definition', {'file': expand('%:p'), 'line': 2, 'offset': 5}],
+  \ g:message
+  AssertEqual {'42': {'open_in_tab': 0}}, ale#definition#GetMap()
+
+Execute(tsserver tab completion requests should be sent):
+  runtime ale_linters/typescript/tsserver.vim
+  call setpos('.', [bufnr(''), 2, 5, 0])
+
+  ALEGoToDefinitionInTab
+
+  AssertEqual
+  \ 'function(''ale#definition#HandleTSServerResponse'')',
+  \ string(g:Callback)
+  AssertEqual
+  \ [0, 'ts@definition', {'file': expand('%:p'), 'line': 2, 'offset': 5}],
+  \ g:message
+  AssertEqual {'42': {'open_in_tab': 1}}, ale#definition#GetMap()