Close #1428 Implement LSP hover-like functionality for tsserver too

autoload/ale/hover.vim

@@ -18,6 +18,15 @@ function! ale#hover#ClearLSPData() abort
 endfunction
 
 function! ale#hover#HandleTSServerResponse(conn_id, response) abort
+    if get(a:response, 'command', '') is# 'quickinfo'
+    \&& has_key(s:hover_map, a:response.request_seq)
+        let l:options = remove(s:hover_map, a:response.request_seq)
+
+        if get(a:response, 'success', v:false) is v:true
+        \&& get(a:response, 'body', v:null) isnot v:null
+            call ale#util#ShowMessage(a:response.body.displayString)
+        endif
+    endif
 endfunction
 
 function! ale#hover#HandleLSPResponse(conn_id, response) abort
@@ -86,8 +95,11 @@ function! s:ShowDetails(linter) abort
     let l:root = l:lsp_details.project_root
 
     if a:linter.lsp is# 'tsserver'
-        " TODO: Implement this.
-        return
+        let l:message = ale#lsp#tsserver_message#Quickinfo(
+        \   l:buffer,
+        \   l:line,
+        \   l:column
+        \)
     else
         " Send a message saying the buffer has changed first, or the
         " hover position probably won't make sense.
@@ -109,7 +121,7 @@ endfunction
 
 function! ale#hover#Show() abort
     for l:linter in ale#linter#Get(&filetype)
-        if !empty(l:linter.lsp) && l:linter.lsp isnot# 'tsserver'
+        if !empty(l:linter.lsp)
             call s:ShowDetails(l:linter)
         endif
     endfor

autoload/ale/lsp/tsserver_message.vim

@@ -69,3 +69,11 @@ function! ale#lsp#tsserver_message#References(buffer, line, column) abort
     \   'file': expand('#' . a:buffer . ':p'),
     \}]
 endfunction
+
+function! ale#lsp#tsserver_message#Quickinfo(buffer, line, column) abort
+    return [0, 'ts@quickinfo', {
+    \   'line': a:line,
+    \   'offset': a:column,
+    \   'file': expand('#' . a:buffer . ':p'),
+    \}]
+endfunction

test/lsp/test_lsp_client_messages.vader

@@ -275,3 +275,16 @@ Execute(ale#lsp#tsserver_message#References() should return correct messages):
   \   }
   \ ],
   \ ale#lsp#tsserver_message#References(bufnr(''), 347, 12)
+
+Execute(ale#lsp#tsserver_message#Quickinfo() should return correct messages):
+  AssertEqual
+  \ [
+  \   0,
+  \   'ts@quickinfo',
+  \   {
+  \     'file': ale#path#Simplify(g:dir . '/foo/bar.ts'),
+  \     'line': 347,
+  \     'offset': 12,
+  \   }
+  \ ],
+  \ ale#lsp#tsserver_message#Quickinfo(bufnr(''), 347, 12)

test/test_hover.vader

@@ -70,6 +70,50 @@ Given python(Some Python file):
   somelongerline
   bazxyzxyzxyz
 
+Execute(Other messages for the tsserver handler should be ignored):
+  call ale#hover#HandleTSServerResponse(1, {'command': 'foo'})
+
+Execute(Failed hover responses should be handled correctly):
+  call ale#hover#SetMap({3: {}})
+  call ale#hover#HandleTSServerResponse(
+  \ 1,
+  \ {'command': 'quickinfo', 'request_seq': 3}
+  \)
+  AssertEqual {}, ale#hover#GetMap()
+
+Given typescript(Some typescript file):
+  foo
+  somelongerline
+  bazxyzxyzxyz
+
+Execute(tsserver quickinfo responses will null missing bodies should be handled):
+  call ale#hover#SetMap({3: {}})
+  call ale#hover#HandleTSServerResponse(
+  \ 1,
+  \ {
+  \   'command': 'quickinfo',
+  \   'request_seq': 3,
+  \   'success': v:true,
+  \ }
+  \)
+
+  AssertEqual {}, ale#hover#GetMap()
+
+Execute(tsserver quickinfo displayString values should be displayed):
+  call ale#hover#SetMap({3: {}})
+  call ale#hover#HandleTSServerResponse(
+  \ 1,
+  \ {
+  \   'command': 'quickinfo',
+  \   'request_seq': 3,
+  \   'success': v:true,
+  \   'body': {'displayString': 'foo bar'},
+  \ }
+  \)
+
+  AssertEqual ['foo bar'], g:echo_list
+  AssertEqual {}, ale#hover#GetMap()
+
 Execute(LSP hover responses with just a string should be handled):
   call HandleValidLSPResult({'contents': 'foobar'})