Support for LSP/tsserver Code Actions (#3437)

* Added tsserver and LSP code action support.
* tsserver refactors support added.
* Handling special case when new text is added after new line symbol.
* ale#code_action#ApplyChanges simplified.
* Initial attempt on LSP Code Actions.
* workspace/executeCommand added.
* Some null checks added.
* Add last column to LSP Code Action message.
* Pass diagnostics to LSP code action.

Previously ApplyChanges code was applied from top-to-bottom that required 
extra parameters to track progress and there was bug. I have changed code
to bottom-to-top approach as that does not require those extra parameters
and solved the bug.

Tested with typescript-language-server and it is working.

15 files changed, 1258 insertions, 84 deletions

diff --git a/ale_linters/python/jedils.vim b/ale_linters/python/jedils.vim
new file mode 100644
index 00000000..eae5fb07
--- /dev/null
+++ b/ale_linters/python/jedils.vim
@@ -0,0 +1,34 @@
+" Author: Dalius Dobravolskas <dalius.dobravolskas@gmail.com>
+" Description: https://github.com/pappasam/jedi-language-server
+
+call ale#Set('python_jedils_executable', 'jedi-language-server')
+call ale#Set('python_jedils_use_global', get(g:, 'ale_use_global_executables', 0))
+call ale#Set('python_jedils_auto_pipenv', 0)
+
+function! ale_linters#python#jedils#GetExecutable(buffer) abort
+    if (ale#Var(a:buffer, 'python_auto_pipenv') || ale#Var(a:buffer, 'python_jedils_auto_pipenv'))
+    \ && ale#python#PipenvPresent(a:buffer)
+        return 'pipenv'
+    endif
+
+    return ale#python#FindExecutable(a:buffer, 'python_jedils', ['jedi-language-server'])
+endfunction
+
+function! ale_linters#python#jedils#GetCommand(buffer) abort
+    let l:executable = ale_linters#python#jedils#GetExecutable(a:buffer)
+
+    let l:exec_args = l:executable =~? 'pipenv$'
+    \   ? ' run jedi-language-server'
+    \   : ''
+
+    return ale#Escape(l:executable) . l:exec_args
+endfunction
+
+call ale#linter#Define('python', {
+\   'name': 'jedils',
+\   'lsp': 'stdio',
+\   'executable': function('ale_linters#python#jedils#GetExecutable'),
+\   'command': function('ale_linters#python#jedils#GetCommand'),
+\   'project_root': function('ale#python#FindProjectRoot'),
+\   'completion_filter': 'ale#completion#python#CompletionItemFilter',
+\})
diff --git a/autoload/ale/code_action.vim b/autoload/ale/code_action.vim
index 42f4f265..4dbb2d08 100644
--- a/autoload/ale/code_action.vim
+++ b/autoload/ale/code_action.vim
@@ -33,35 +33,35 @@ endfunction
 
 function! s:ChangeCmp(left, right) abort
     if a:left.start.line < a:right.start.line
-        return -1
+        return 1
     endif
 
     if a:left.start.line > a:right.start.line
-        return 1
+        return -1
     endif
 
     if a:left.start.offset < a:right.start.offset
-        return -1
+        return 1
     endif
 
     if a:left.start.offset > a:right.start.offset
-        return 1
+        return -1
     endif
 
     if a:left.end.line < a:right.end.line
-        return -1
+        return 1
     endif
 
     if a:left.end.line > a:right.end.line
-        return 1
+        return -1
     endif
 
     if a:left.end.offset < a:right.end.offset
-        return -1
+        return 1
     endif
 
     if a:left.end.offset > a:right.end.offset
-        return 1
+        return -1
     endif
 
     return 0
@@ -85,29 +85,14 @@ function! ale#code_action#ApplyChanges(filename, changes, should_save) abort
         let l:pos = [1, 1]
     endif
 
-    " We have to keep track of how many lines we have added, and offset
-    " changes accordingly.
-    let l:line_offset = 0
-    let l:column_offset = 0
-    let l:last_end_line = 0
-
-    " Changes have to be sorted so we apply them from top-to-bottom.
+    " Changes have to be sorted so we apply them from bottom-to-top
     for l:code_edit in sort(copy(a:changes), function('s:ChangeCmp'))
-        if l:code_edit.start.line isnot l:last_end_line
-            let l:column_offset = 0
-        endif
-
-        let l:line = l:code_edit.start.line + l:line_offset
-        let l:column = l:code_edit.start.offset + l:column_offset
-        let l:end_line = l:code_edit.end.line + l:line_offset
-        let l:end_column = l:code_edit.end.offset + l:column_offset
+        let l:line = l:code_edit.start.line
+        let l:column = l:code_edit.start.offset
+        let l:end_line = l:code_edit.end.line
+        let l:end_column = l:code_edit.end.offset
         let l:text = l:code_edit.newText
 
-        let l:cur_line = l:pos[0]
-        let l:cur_column = l:pos[1]
-
-        let l:last_end_line = l:end_line
-
         " Adjust the ends according to previous edits.
         if l:end_line > len(l:lines)
             let l:end_line_len = 0
@@ -125,6 +110,12 @@ function! ale#code_action#ApplyChanges(filename, changes, should_save) abort
             let l:start = l:lines[: l:line - 2]
         endif
 
+        " Special case when text must be added after new line
+        if l:column > len(l:lines[l:line - 1])
+            call extend(l:start, [l:lines[l:line - 1]])
+            let l:column = 1
+        endif
+
         if l:column is 1
             " We need to handle column 1 specially, because we can't slice an
             " empty string ending on index 0.
@@ -140,7 +131,6 @@ function! ale#code_action#ApplyChanges(filename, changes, should_save) abort
         let l:lines = l:start + l:middle + l:lines[l:end_line :]
 
         let l:current_line_offset = len(l:lines) - l:lines_before_change
-        let l:line_offset += l:current_line_offset
         let l:column_offset = len(l:middle[-1]) - l:end_line_len
 
         let l:pos = s:UpdateCursor(l:pos,
@@ -215,3 +205,61 @@ function! s:UpdateCursor(cursor, start, end, offset) abort
 
     return [l:cur_line, l:cur_column]
 endfunction
+
+function! ale#code_action#GetChanges(workspace_edit) abort
+    let l:changes = {}
+
+    if has_key(a:workspace_edit, 'changes') && !empty(a:workspace_edit.changes)
+        return a:workspace_edit.changes
+    elseif has_key(a:workspace_edit, 'documentChanges')
+        let l:document_changes = []
+
+        if type(a:workspace_edit.documentChanges) is v:t_dict
+        \ && has_key(a:workspace_edit.documentChanges, 'edits')
+            call add(l:document_changes, a:workspace_edit.documentChanges)
+        elseif type(a:workspace_edit.documentChanges) is v:t_list
+            let l:document_changes = a:workspace_edit.documentChanges
+        endif
+
+        for l:text_document_edit in l:document_changes
+            let l:filename = l:text_document_edit.textDocument.uri
+            let l:edits = l:text_document_edit.edits
+            let l:changes[l:filename] = l:edits
+        endfor
+    endif
+
+    return l:changes
+endfunction
+
+function! ale#code_action#BuildChangesList(changes_map) abort
+    let l:changes = []
+
+    for l:file_name in keys(a:changes_map)
+        let l:text_edits = a:changes_map[l:file_name]
+        let l:text_changes = []
+
+        for l:edit in l:text_edits
+            let l:range = l:edit.range
+            let l:new_text = l:edit.newText
+
+            call add(l:text_changes, {
+            \ 'start': {
+            \   'line': l:range.start.line + 1,
+            \   'offset': l:range.start.character + 1,
+            \ },
+            \ 'end': {
+            \   'line': l:range.end.line + 1,
+            \   'offset': l:range.end.character + 1,
+            \ },
+            \ 'newText': l:new_text,
+            \})
+        endfor
+
+        call add(l:changes, {
+        \   'fileName': ale#path#FromURI(l:file_name),
+        \   'textChanges': l:text_changes,
+        \})
+    endfor
+
+    return l:changes
+endfunction
diff --git a/autoload/ale/codefix.vim b/autoload/ale/codefix.vim
new file mode 100644
index 00000000..b58f5e4b
--- /dev/null
+++ b/autoload/ale/codefix.vim
@@ -0,0 +1,388 @@
+" Author: Dalius Dobravolskas <dalius.dobravolskas@gmail.com>
+" Description: Code Fix support for tsserver
+
+let s:codefix_map = {}
+
+" Used to get the codefix map in tests.
+function! ale#codefix#GetMap() abort
+    return deepcopy(s:codefix_map)
+endfunction
+
+" Used to set the codefix map in tests.
+function! ale#codefix#SetMap(map) abort
+    let s:codefix_map = a:map
+endfunction
+
+function! ale#codefix#ClearLSPData() abort
+    let s:codefix_map = {}
+endfunction
+
+function! s:message(message) abort
+    call ale#util#Execute('echom ' . string(a:message))
+endfunction
+
+function! ale#codefix#HandleTSServerResponse(conn_id, response) abort
+    if !has_key(a:response, 'request_seq')
+    \ || !has_key(s:codefix_map, a:response.request_seq)
+        return
+    endif
+
+    let l:location = remove(s:codefix_map, a:response.request_seq)
+
+    if get(a:response, 'command', '') is# 'getCodeFixes'
+        if get(a:response, 'success', v:false) is v:false
+            let l:message = get(a:response, 'message', 'unknown')
+            call s:message('Error while getting code fixes. Reason: ' . l:message)
+
+            return
+        endif
+
+        if len(a:response.body) == 0
+            call s:message('No code fixes available.')
+
+            return
+        endif
+
+        let l:code_fix_to_apply = 0
+
+        if len(a:response.body) == 1
+            let l:code_fix_to_apply = 1
+        else
+            let l:codefix_no = 1
+            let l:codefixstring = "Code Fixes:\n"
+
+            for l:codefix in a:response.body
+                let l:codefixstring .= l:codefix_no . ') ' . l:codefix.description . "\n"
+                let l:codefix_no += 1
+            endfor
+
+            let l:codefixstring .= 'Type number and <Enter> (empty cancels): '
+
+            let l:code_fix_to_apply = ale#util#Input(l:codefixstring, '')
+            let l:code_fix_to_apply = str2nr(l:code_fix_to_apply)
+
+            if l:code_fix_to_apply == 0
+                return
+            endif
+        endif
+
+        let l:changes = a:response.body[l:code_fix_to_apply - 1].changes
+
+        call ale#code_action#HandleCodeAction({
+        \ 'description': 'codefix',
+        \ 'changes': l:changes,
+        \}, {})
+    elseif get(a:response, 'command', '') is# 'getApplicableRefactors'
+        if get(a:response, 'success', v:false) is v:false
+            let l:message = get(a:response, 'message', 'unknown')
+            call s:message('Error while getting applicable refactors. Reason: ' . l:message)
+
+            return
+        endif
+
+        if len(a:response.body) == 0
+            call s:message('No applicable refactors available.')
+
+            return
+        endif
+
+        let l:refactors = []
+
+        for l:item in a:response.body
+            for l:action in l:item.actions
+                call add(l:refactors, {
+                \   'name': l:action.description,
+                \   'id': [l:item.name, l:action.name],
+                \})
+            endfor
+        endfor
+
+        let l:refactor_no = 1
+        let l:refactorstring = "Applicable refactors:\n"
+
+        for l:refactor in l:refactors
+            let l:refactorstring .= l:refactor_no . ') ' . l:refactor.name . "\n"
+            let l:refactor_no += 1
+        endfor
+
+        let l:refactorstring .= 'Type number and <Enter> (empty cancels): '
+
+        let l:refactor_to_apply = ale#util#Input(l:refactorstring, '')
+        let l:refactor_to_apply = str2nr(l:refactor_to_apply)
+
+        if l:refactor_to_apply == 0
+            return
+        endif
+
+        let l:id = l:refactors[l:refactor_to_apply - 1].id
+
+        let l:message = ale#lsp#tsserver_message#GetEditsForRefactor(
+        \   l:location.buffer,
+        \   l:location.line,
+        \   l:location.column,
+        \   l:location.end_line,
+        \   l:location.end_column,
+        \   l:id[0],
+        \   l:id[1],
+        \)
+
+        let l:request_id = ale#lsp#Send(l:location.connection_id, l:message)
+
+        let s:codefix_map[l:request_id] = l:location
+    elseif get(a:response, 'command', '') is# 'getEditsForRefactor'
+        if get(a:response, 'success', v:false) is v:false
+            let l:message = get(a:response, 'message', 'unknown')
+            call s:message('Error while getting edits for refactor. Reason: ' . l:message)
+
+            return
+        endif
+
+        call ale#code_action#HandleCodeAction({
+        \ 'description': 'editsForRefactor',
+        \ 'changes': a:response.body.edits,
+        \}, {})
+    endif
+endfunction
+
+function! ale#codefix#HandleLSPResponse(conn_id, response) abort
+    if has_key(a:response, 'method')
+    \ && a:response.method is# 'workspace/applyEdit'
+    \ && has_key(a:response, 'params')
+        let l:params = a:response.params
+
+        let l:changes_map = ale#code_action#GetChanges(l:params.edit)
+
+        if empty(l:changes_map)
+            return
+        endif
+
+        let l:changes = ale#code_action#BuildChangesList(l:changes_map)
+
+        call ale#code_action#HandleCodeAction({
+        \ 'description': 'applyEdit',
+        \ 'changes': l:changes,
+        \}, {})
+    elseif has_key(a:response, 'id')
+    \&& has_key(s:codefix_map, a:response.id)
+        let l:location = remove(s:codefix_map, a:response.id)
+
+        if !has_key(a:response, 'result')
+        \ || type(a:response.result) != v:t_list
+        \ || len(a:response.result) == 0
+            call s:message('No code actions received from server')
+
+            return
+        endif
+
+        let l:codeaction_no = 1
+        let l:codeactionstring = "Code Fixes:\n"
+
+        for l:codeaction in a:response.result
+            let l:codeactionstring .= l:codeaction_no . ') ' . l:codeaction.title . "\n"
+            let l:codeaction_no += 1
+        endfor
+
+        let l:codeactionstring .= 'Type number and <Enter> (empty cancels): '
+
+        let l:codeaction_to_apply = ale#util#Input(l:codeactionstring, '')
+        let l:codeaction_to_apply = str2nr(l:codeaction_to_apply)
+
+        if l:codeaction_to_apply == 0
+            return
+        endif
+
+        let l:item = a:response.result[l:codeaction_to_apply - 1]
+
+        if has_key(l:item, 'command')
+        \ && type(l:item.command) == v:t_dict
+            let l:command = l:item.command
+            let l:message = ale#lsp#message#ExecuteCommand(
+            \ l:command.command,
+            \ l:command.arguments,
+            \)
+
+            let l:request_id = ale#lsp#Send(l:location.connection_id, l:message)
+        elseif has_key(l:item, 'edit') || has_key(l:item, 'arguments')
+            if has_key(l:item, 'edit')
+                let l:topass = l:item.edit
+            else
+                let l:topass = l:item.arguments[0]
+            endif
+
+            let l:changes_map = ale#code_action#GetChanges(l:topass)
+
+            if empty(l:changes_map)
+                return
+            endif
+
+            let l:changes = ale#code_action#BuildChangesList(l:changes_map)
+
+            call ale#code_action#HandleCodeAction({
+            \ 'description': 'codeaction',
+            \ 'changes': l:changes,
+            \}, {})
+        endif
+    endif
+endfunction
+
+
+function! s:OnReady(line, column, end_line, end_column, linter, lsp_details) abort
+    let l:id = a:lsp_details.connection_id
+
+    if !ale#lsp#HasCapability(l:id, 'code_actions')
+        return
+    endif
+
+    let l:buffer = a:lsp_details.buffer
+
+    if a:linter.lsp is# 'tsserver'
+        if a:line == a:end_line && a:column == a:end_column
+            if !has_key(g:ale_buffer_info, l:buffer)
+                return
+            endif
+
+            let l:nearest_error = v:null
+            let l:nearest_error_diff = -1
+
+            for l:error in get(g:ale_buffer_info[l:buffer], 'loclist', [])
+                if has_key(l:error, 'code') && l:error.lnum == a:line
+                    let l:diff = abs(l:error.col - a:column)
+
+                    if l:nearest_error_diff == -1 || l:diff < l:nearest_error_diff
+                        let l:nearest_error_diff = l:diff
+                        let l:nearest_error = l:error.code
+                    endif
+                endif
+            endfor
+
+            let l:message = ale#lsp#tsserver_message#GetCodeFixes(
+            \   l:buffer,
+            \   a:line,
+            \   a:column,
+            \   a:line,
+            \   a:column,
+            \   [l:nearest_error],
+            \)
+        else
+            let l:message = ale#lsp#tsserver_message#GetApplicableRefactors(
+            \   l:buffer,
+            \   a:line,
+            \   a:column,
+            \   a:end_line,
+            \   a:end_column,
+            \)
+        endif
+    else
+        " Send a message saying the buffer has changed first, otherwise
+        " completions won't know what text is nearby.
+        call ale#lsp#NotifyForChanges(l:id, l:buffer)
+
+        if a:line == a:end_line && a:column == a:end_column
+            if !has_key(g:ale_buffer_info, l:buffer)
+                return
+            endif
+
+            let l:nearest_error = v:null
+            let l:nearest_error_diff = -1
+
+            for l:error in get(g:ale_buffer_info[l:buffer], 'loclist', [])
+                if has_key(l:error, 'code') && l:error.lnum == a:line
+                    let l:diff = abs(l:error.col - a:column)
+
+                    if l:nearest_error_diff == -1 || l:diff < l:nearest_error_diff
+                        let l:nearest_error_diff = l:diff
+                        let l:nearest_error = l:error
+                    endif
+                endif
+            endfor
+
+            let l:diagnostics = []
+
+            if l:nearest_error isnot v:null
+                let l:diagnostics = [{
+                \ 'code': l:nearest_error.code,
+                \ 'message': l:nearest_error.text,
+                \ 'range': {
+                \     'start': { 'line': l:nearest_error.lnum - 1, 'character': l:nearest_error.col - 1 },
+                \     'end': { 'line': l:nearest_error.end_lnum - 1, 'character': l:nearest_error.end_col - 1 }
+                \}
+                \}]
+            endif
+
+            let l:message = ale#lsp#message#CodeAction(
+            \   l:buffer,
+            \   a:line,
+            \   a:column,
+            \   a:end_line,
+            \   a:end_column,
+            \   l:diagnostics,
+            \)
+        else
+            let l:message = ale#lsp#message#CodeAction(
+            \   l:buffer,
+            \   a:line,
+            \   a:column,
+            \   a:end_line,
+            \   a:end_column,
+            \   [],
+            \)
+        endif
+    endif
+
+    let l:Callback = a:linter.lsp is# 'tsserver'
+    \   ? function('ale#codefix#HandleTSServerResponse')
+    \   : function('ale#codefix#HandleLSPResponse')
+
+    call ale#lsp#RegisterCallback(l:id, l:Callback)
+
+    let l:request_id = ale#lsp#Send(l:id, l:message)
+
+    let s:codefix_map[l:request_id] = {
+    \ 'connection_id': l:id,
+    \ 'buffer': l:buffer,
+    \ 'line': a:line,
+    \ 'column': a:column,
+    \ 'end_line': a:end_line,
+    \ 'end_column': a:end_column,
+    \}
+endfunction
+
+function! s:ExecuteGetCodeFix(linter, range) abort
+    let l:buffer = bufnr('')
+
+    if a:range == 0
+        let [l:line, l:column] = getpos('.')[1:2]
+        let l:end_line = l:line
+        let l:end_column = l:column
+    else
+        let [l:line, l:column] = getpos("'<")[1:2]
+        let [l:end_line, l:end_column] = getpos("'>")[1:2]
+    endif
+
+    let l:column = min([l:column, len(getline(l:line))])
+    let l:end_column = min([l:end_column, len(getline(l:end_line))])
+
+    let l:Callback = function(
+    \ 's:OnReady', [l:line, l:column, l:end_line, l:end_column])
+    call ale#lsp_linter#StartLSP(l:buffer, a:linter, l:Callback)
+endfunction
+
+function! ale#codefix#Execute(range) abort
+    let l:lsp_linters = []
+
+    for l:linter in ale#linter#Get(&filetype)
+        if !empty(l:linter.lsp)
+            call add(l:lsp_linters, l:linter)
+        endif
+    endfor
+
+    if empty(l:lsp_linters)
+        call s:message('No active LSPs')
+
+        return
+    endif
+
+    for l:lsp_linter in l:lsp_linters
+        call s:ExecuteGetCodeFix(l:lsp_linter, a:range)
+    endfor
+endfunction
diff --git a/autoload/ale/completion.vim b/autoload/ale/completion.vim
index efbf0fd5..48e9bf7c 100644
--- a/autoload/ale/completion.vim
+++ b/autoload/ale/completion.vim
@@ -617,6 +617,7 @@ function! ale#completion#ParseLSPCompletions(response) abort
         let l:user_data = {'_ale_completion_item': 1}
 
         if has_key(l:item, 'additionalTextEdits')
+        \ && l:item.additionalTextEdits isnot v:null
             let l:text_changes = []
 
             for l:edit in l:item.additionalTextEdits
diff --git a/autoload/ale/lsp.vim b/autoload/ale/lsp.vim
index 7d99e9d2..cb0573aa 100644
--- a/autoload/ale/lsp.vim
+++ b/autoload/ale/lsp.vim
@@ -44,6 +44,7 @@ function! ale#lsp#Register(executable_or_address, project, init_options) abort
         \       'definition': 0,
         \       'typeDefinition': 0,
         \       'symbol_search': 0,
+        \       'code_actions': 0,
         \   },
         \}
     endif
@@ -219,6 +220,14 @@ function! s:UpdateCapabilities(conn, capabilities) abort
         let a:conn.capabilities.rename = 1
     endif
 
+    if get(a:capabilities, 'codeActionProvider') is v:true
+        let a:conn.capabilities.code_actions = 1
+    endif
+
+    if type(get(a:capabilities, 'codeActionProvider')) is v:t_dict
+        let a:conn.capabilities.code_actions = 1
+    endif
+
     if !empty(get(a:capabilities, 'completionProvider'))
         let a:conn.capabilities.completion = 1
     endif
@@ -350,6 +359,7 @@ function! ale#lsp#MarkConnectionAsTsserver(conn_id) abort
     let l:conn.capabilities.definition = 1
     let l:conn.capabilities.symbol_search = 1
     let l:conn.capabilities.rename = 1
+    let l:conn.capabilities.code_actions = 1
 endfunction
 
 function! s:SendInitMessage(conn) abort
diff --git a/autoload/ale/lsp/message.vim b/autoload/ale/lsp/message.vim
index 5b0cb8b7..38be4da6 100644
--- a/autoload/ale/lsp/message.vim
+++ b/autoload/ale/lsp/message.vim
@@ -172,3 +172,25 @@ function! ale#lsp#message#Rename(buffer, line, column, new_name) abort
     \   'newName': a:new_name,
     \}]
 endfunction
+
+function! ale#lsp#message#CodeAction(buffer, line, column, end_line, end_column, diagnostics) abort
+    return [0, 'textDocument/codeAction', {
+    \   'textDocument': {
+    \       'uri': ale#path#ToURI(expand('#' . a:buffer . ':p')),
+    \   },
+    \   'range': {
+    \       'start': {'line': a:line - 1, 'character': a:column - 1},
+    \       'end': {'line': a:end_line - 1, 'character': a:end_column},
+    \   },
+    \   'context': {
+    \       'diagnostics': a:diagnostics
+    \   },
+    \}]
+endfunction
+
+function! ale#lsp#message#ExecuteCommand(command, arguments) abort
+    return [0, 'workspace/executeCommand', {
+    \   'command': a:command,
+    \   'arguments': a:arguments,
+    \}]
+endfunction
diff --git a/autoload/ale/lsp/response.vim b/autoload/ale/lsp/response.vim
index 30da77e1..a4f80980 100644
--- a/autoload/ale/lsp/response.vim
+++ b/autoload/ale/lsp/response.vim
@@ -56,6 +56,7 @@ function! ale#lsp#response#ReadDiagnostics(response) abort
         endif
 
         if has_key(l:diagnostic, 'relatedInformation')
+        \ && l:diagnostic.relatedInformation isnot v:null
             let l:related = deepcopy(l:diagnostic.relatedInformation)
             call map(l:related, {key, val ->
             \   ale#path#FromURI(val.location.uri) .
diff --git a/autoload/ale/lsp/tsserver_message.vim b/autoload/ale/lsp/tsserver_message.vim
index b9fafaa0..3c1b47ed 100644
--- a/autoload/ale/lsp/tsserver_message.vim
+++ b/autoload/ale/lsp/tsserver_message.vim
@@ -103,3 +103,39 @@ function! ale#lsp#tsserver_message#OrganizeImports(buffer) abort
     \   },
     \}]
 endfunction
+
+function! ale#lsp#tsserver_message#GetCodeFixes(buffer, line, column, end_line, end_column, error_codes) abort
+    " The lines and columns are 1-based.
+    " The errors codes must be a list of tsserver error codes to fix.
+    return [0, 'ts@getCodeFixes', {
+    \   'startLine': a:line,
+    \   'startOffset': a:column,
+    \   'endLine': a:end_line,
+    \   'endOffset': a:end_column + 1,
+    \   'file': expand('#' . a:buffer . ':p'),
+    \   'errorCodes': a:error_codes,
+    \}]
+endfunction
+
+function! ale#lsp#tsserver_message#GetApplicableRefactors(buffer, line, column, end_line, end_column) abort
+    " The arguments for this request can also be just 'line' and 'offset'
+    return [0, 'ts@getApplicableRefactors', {
+    \   'startLine': a:line,
+    \   'startOffset': a:column,
+    \   'endLine': a:end_line,
+    \   'endOffset': a:end_column + 1,
+    \   'file': expand('#' . a:buffer . ':p'),
+    \}]
+endfunction
+
+function! ale#lsp#tsserver_message#GetEditsForRefactor(buffer, line, column, end_line, end_column, refactor, action) abort
+    return [0, 'ts@getEditsForRefactor', {
+    \   'startLine': a:line,
+    \   'startOffset': a:column,
+    \   'endLine': a:end_line,
+    \   'endOffset': a:end_column + 1,
+    \   'file': expand('#' . a:buffer . ':p'),
+    \   'refactor': a:refactor,
+    \   'action': a:action,
+    \}]
+endfunction
diff --git a/autoload/ale/rename.vim b/autoload/ale/rename.vim
index 8190411d..0d074c24 100644
--- a/autoload/ale/rename.vim
+++ b/autoload/ale/rename.vim
@@ -90,31 +90,6 @@ function! ale#rename#HandleTSServerResponse(conn_id, response) abort
     \)
 endfunction
 
-function! s:getChanges(workspace_edit) abort
-    let l:changes = {}
-
-    if has_key(a:workspace_edit, 'changes') && !empty(a:workspace_edit.changes)
-        return a:workspace_edit.changes
-    elseif has_key(a:workspace_edit, 'documentChanges')
-        let l:document_changes = []
-
-        if type(a:workspace_edit.documentChanges) is v:t_dict
-        \ && has_key(a:workspace_edit.documentChanges, 'edits')
-            call add(l:document_changes, a:workspace_edit.documentChanges)
-        elseif type(a:workspace_edit.documentChanges) is v:t_list
-            let l:document_changes = a:workspace_edit.documentChanges
-        endif
-
-        for l:text_document_edit in l:document_changes
-            let l:filename = l:text_document_edit.textDocument.uri
-            let l:edits = l:text_document_edit.edits
-            let l:changes[l:filename] = l:edits
-        endfor
-    endif
-
-    return l:changes
-endfunction
-
 function! ale#rename#HandleLSPResponse(conn_id, response) abort
     if has_key(a:response, 'id')
     \&& has_key(s:rename_map, a:response.id)
@@ -126,7 +101,7 @@ function! ale#rename#HandleLSPResponse(conn_id, response) abort
             return
         endif
 
-        let l:changes_map = s:getChanges(a:response.result)
+        let l:changes_map = ale#code_action#GetChanges(a:response.result)
 
         if empty(l:changes_map)
             call s:message('No changes received from server')
@@ -134,34 +109,7 @@ function! ale#rename#HandleLSPResponse(conn_id, response) abort
             return
         endif
 
-        let l:changes = []
-
-        for l:file_name in keys(l:changes_map)
-            let l:text_edits = l:changes_map[l:file_name]
-            let l:text_changes = []
-
-            for l:edit in l:text_edits
-                let l:range = l:edit.range
-                let l:new_text = l:edit.newText
-
-                call add(l:text_changes, {
-                \ 'start': {
-                \   'line': l:range.start.line + 1,
-                \   'offset': l:range.start.character + 1,
-                \ },
-                \ 'end': {
-                \   'line': l:range.end.line + 1,
-                \   'offset': l:range.end.character + 1,
-                \ },
-                \ 'newText': l:new_text,
-                \})
-            endfor
-
-            call add(l:changes, {
-            \   'fileName': ale#path#FromURI(l:file_name),
-            \   'textChanges': l:text_changes,
-            \})
-        endfor
+        let l:changes = ale#code_action#BuildChangesList(l:changes_map)
 
         call ale#code_action#HandleCodeAction(
         \   {
diff --git a/doc/ale.txt b/doc/ale.txt
index eb8f0275..4263f698 100644
--- a/doc/ale.txt
+++ b/doc/ale.txt
@@ -3106,6 +3106,18 @@ ALERename                                                           *ALERename*
   in those files will not be updated.
 
 
+ALECodeAction                                                   *ALECodeAction*
+
+  Code Actions support for `tsserver`.
+
+  There are two different kind of actions supported for `tsserver`. If run in
+  normal mode then code fix will be attempted if there is error in that line.
+  If there are multiple code fixes available use will be shown input to choose
+  one. In visual mode `tsserver` will be queries for applicable refactors
+  (e.g. extract to constant or extract to function) and user will be given
+  choice to select the one he/she likes.
+
+
 ALERepeatSelection                                         *ALERepeatSelection*
 
   Repeat the last selection displayed in the preview window.
diff --git a/plugin/ale.vim b/plugin/ale.vim
index 32ec14ac..7472ea8c 100644
--- a/plugin/ale.vim
+++ b/plugin/ale.vim
@@ -240,6 +240,8 @@ command! -bar ALEImport :call ale#completion#Import()
 " Rename symbols using tsserver and LSP
 command! -bar -bang ALERename :call ale#rename#Execute({'force_save': '<bang>' is# '!'})
 
+command! -bar -range ALECodeAction :call ale#codefix#Execute(<range>)
+
 " Organize import statements using tsserver
 command! -bar ALEOrganizeImports :call ale#organize_imports#Execute()
 
@@ -283,6 +285,7 @@ nnoremap <silent> <Plug>(ale_documentation) :ALEDocumentation<Return>
 inoremap <silent> <Plug>(ale_complete) <C-\><C-O>:ALEComplete<Return>
 nnoremap <silent> <Plug>(ale_import) :ALEImport<Return>
 nnoremap <silent> <Plug>(ale_rename) :ALERename<Return>
+nnoremap <silent> <Plug>(ale_code_action) :ALECodeAction<Return>
 nnoremap <silent> <Plug>(ale_repeat_selection) :ALERepeatSelection<Return>
 
 " Set up autocmd groups now.
diff --git a/test/lsp/test_other_initialize_message_handling.vader b/test/lsp/test_other_initialize_message_handling.vader
index b6ef852a..f3b53843 100644
--- a/test/lsp/test_other_initialize_message_handling.vader
+++ b/test/lsp/test_other_initialize_message_handling.vader
@@ -23,6 +23,7 @@ Before:
   \   'completion_trigger_characters': [],
   \   'definition': 0,
   \   'symbol_search': 0,
+  \   'code_actions': 0,
   \ },
   \}
 
@@ -102,6 +103,7 @@ Execute(Capabilities should bet set up correctly):
   \   'definition': 1,
   \   'symbol_search': 1,
   \   'rename': 1,
+  \   'code_actions': 1,
   \ },
   \ b:conn.capabilities
   AssertEqual [[1, 'initialized', {}]], g:message_list
@@ -125,7 +127,7 @@ Execute(Disabled capabilities should be recognised correctly):
   \     'referencesProvider': v:false,
   \     'textDocumentSync': 2,
   \     'documentFormattingProvider': v:true,
-  \     'codeActionProvider': v:true,
+  \     'codeActionProvider': v:false,
   \     'signatureHelpProvider': {
   \       'triggerCharacters': ['(', ','],
   \     },
@@ -146,6 +148,7 @@ Execute(Disabled capabilities should be recognised correctly):
   \   'definition': 0,
   \   'symbol_search': 0,
   \   'rename': 0,
+  \   'code_actions': 0,
   \ },
   \ b:conn.capabilities
   AssertEqual [[1, 'initialized', {}]], g:message_list
@@ -197,6 +200,7 @@ Execute(Capabilities should be enabled when send as Dictionaries):
   \   'typeDefinition': 1,
   \   'symbol_search': 1,
   \   'rename': 1,
+  \   'code_actions': 1,
   \ },
   \ b:conn.capabilities
   AssertEqual [[1, 'initialized', {}]], g:message_list
diff --git a/test/test_code_action.vader b/test/test_code_action.vader
index 2e5d1381..7eabb759 100644
--- a/test/test_code_action.vader
+++ b/test/test_code_action.vader
@@ -3,6 +3,9 @@ Before:
 
   let g:ale_enabled = 0
 
+  " Enable fix end-of-line as tests below expect that
+  set fixeol
+
   runtime autoload/ale/code_action.vim
   runtime autoload/ale/util.vim
 
@@ -211,6 +214,7 @@ Execute(End of file can be modified):
   \)
 
   AssertEqual g:test.text + [
+  \  '',
   \  'type A: string',
   \  'type B: number',
   \  '',
diff --git a/test/test_code_action_python.vader b/test/test_code_action_python.vader
new file mode 100644
index 00000000..fd30633d
--- /dev/null
+++ b/test/test_code_action_python.vader
@@ -0,0 +1,59 @@
+Given python(An example Python file):
+  def main():
+      a = 1
+      c = a + 1
+
+Execute():
+  let g:changes = [
+  \ {'end': {'offset': 7, 'line': 1}, 'newText': 'func_qtffgsv', 'start': {'offset': 5, 'line': 1}},
+  \ {'end': {'offset': 9, 'line': 1}, 'newText': '', 'start': {'offset': 8, 'line': 1}},
+  \ {'end': {'offset': 15, 'line': 3}, 'newText': "    return c\n\n\ndef main():\n    c = func_qtffgsvi()\n", 'start': {'offset': 15, 'line': 3}}
+  \]
+
+  call ale#code_action#ApplyChanges(expand('%:p'), g:changes, 0)
+
+Expect(The changes should be applied correctly):
+  def func_qtffgsvi():
+      a = 1
+      c = a + 1
+      return c
+
+
+  def main():
+      c = func_qtffgsvi()
+
+
+Given python(Second python example):
+  import sys
+  import exifread
+
+  def main():
+      with open(sys.argv[1], 'rb') as f:
+          exif = exifread.process_file(f)
+          dt = str(exif['Image DateTime'])
+          date = dt[:10].replace(':', '-')
+
+Execute():
+  let g:changes = [
+  \ {'end': {'offset': 16, 'line': 2}, 'newText': "\n\ndef func_ivlpdpao(f):\n    exif = exifread.process_file(f)\n    dt = str(exif['Image DateTime'])\n    date = dt[:10].replace(':', '-')\n    return date\n", 'start': {'offset': 16, 'line': 2}},
+  \ {'end': {'offset': 32, 'line': 6}, 'newText': 'date = func', 'start': {'offset': 9, 'line': 6}},
+  \ {'end': {'offset': 42, 'line': 8}, 'newText': "ivlpdpao(f)\n", 'start': {'offset': 33, 'line': 6}}
+  \]
+
+  call ale#code_action#ApplyChanges(expand('%:p'), g:changes, 0)
+
+Expect(The changes should be applied correctly):
+  import sys
+  import exifread
+
+
+  def func_ivlpdpao(f):
+      exif = exifread.process_file(f)
+      dt = str(exif['Image DateTime'])
+      date = dt[:10].replace(':', '-')
+      return date
+
+
+  def main():
+      with open(sys.argv[1], 'rb') as f:
+          date = func_ivlpdpao(f)
diff --git a/test/test_codefix.vader b/test/test_codefix.vader
new file mode 100644
index 00000000..63275d7f
--- /dev/null
+++ b/test/test_codefix.vader
@@ -0,0 +1,604 @@
+Before:
+  call ale#test#SetDirectory('/testplugin/test')
+  call ale#test#SetFilename('dummy.txt')
+  Save g:ale_buffer_info
+
+  let g:ale_buffer_info = {}
+
+  let g:old_filename = expand('%:p')
+  let g:Callback = ''
+  let g:expr_list = []
+  let g:message_list = []
+  let g:handle_code_action_called = 0
+  let g:code_actions = []
+  let g:options = {}
+  let g:capability_checked = ''
+  let g:conn_id = v:null
+  let g:InitCallback = v:null
+
+  runtime autoload/ale/lsp_linter.vim
+  runtime autoload/ale/lsp.vim
+  runtime autoload/ale/util.vim
+  runtime autoload/ale/codefix.vim
+  runtime autoload/ale/code_action.vim
+
+  function! ale#lsp_linter#StartLSP(buffer, linter, Callback) abort
+    let g:conn_id = ale#lsp#Register('executable', '/foo/bar', {})
+    call ale#lsp#MarkDocumentAsOpen(g:conn_id, a:buffer)
+
+    if a:linter.lsp is# 'tsserver'
+        call ale#lsp#MarkConnectionAsTsserver(g:conn_id)
+    endif
+
+    let l:details = {
+    \ 'command': 'foobar',
+    \ 'buffer': a:buffer,
+    \ 'connection_id': g:conn_id,
+    \ 'project_root': '/foo/bar',
+    \}
+
+    let g:InitCallback = {-> ale#lsp_linter#OnInit(a:linter, l:details, a:Callback)}
+  endfunction
+
+  function! ale#lsp#HasCapability(conn_id, capability) abort
+    let g:capability_checked = a:capability
+
+    return 1
+  endfunction
+
+  function! ale#lsp#RegisterCallback(conn_id, callback) abort
+    let g:Callback = a:callback
+  endfunction
+
+  function! ale#lsp#Send(conn_id, message) abort
+    call add(g:message_list, a:message)
+
+    return 42
+  endfunction
+
+  function! ale#util#Execute(expr) abort
+    call add(g:expr_list, a:expr)
+  endfunction
+
+  function! ale#code_action#HandleCodeAction(code_action, options) abort
+    let g:handle_code_action_called = 1
+    Assert !get(a:options, 'should_save')
+    call add(g:code_actions, a:code_action)
+  endfunction
+
+  function! ale#util#Input(message, value) abort
+    return '2'
+  endfunction
+
+After:
+  Restore
+
+  if g:conn_id isnot v:null
+    call ale#lsp#RemoveConnectionWithID(g:conn_id)
+  endif
+
+  call ale#test#RestoreDirectory()
+  call ale#linter#Reset()
+
+  unlet! g:capability_checked
+  unlet! g:InitCallback
+  unlet! g:old_filename
+  unlet! g:conn_id
+  unlet! g:Callback
+  unlet! g:message_list
+  unlet! g:expr_list
+  unlet! b:ale_linters
+  unlet! g:options
+  unlet! g:code_actions
+  unlet! g:handle_code_action_called
+
+  runtime autoload/ale/lsp_linter.vim
+  runtime autoload/ale/lsp.vim
+  runtime autoload/ale/util.vim
+  runtime autoload/ale/codefix.vim
+  runtime autoload/ale/code_action.vim
+
+Execute(Failed codefix responses should be handled correctly):
+  call ale#codefix#HandleTSServerResponse(
+  \ 1,
+  \ {'command': 'getCodeFixes', 'request_seq': 3}
+  \)
+  AssertEqual g:handle_code_action_called, 0
+
+
+
+Given typescript(Some typescript file):
+  foo
+  somelongerline
+  bazxyzxyzxyz
+
+Execute(getCodeFixes from tsserver should be handled):
+  call ale#codefix#SetMap({3: {}})
+  call ale#codefix#HandleTSServerResponse(1, {
+    \ 'command': 'getCodeFixes',
+    \ 'request_seq': 3,
+    \ 'success': v:true,
+    \ 'type': 'response',
+    \ 'body': [
+    \   {
+    \     'description': 'Import default "x" from module "./z"',
+    \     'fixName': 'import',
+    \     'changes': [
+    \       {
+    \         'fileName': "/foo/bar/file1.ts",
+    \         'textChanges': [
+    \           {
+    \             'end': {
+    \               'line': 2,
+    \               'offset': 1,
+    \             },
+    \             'newText': 'import x from "./z";^@',
+    \             'start': {
+    \               'line': 2,
+    \               'offset': 1,
+    \             }
+    \           }
+    \         ]
+    \       }
+    \     ]
+    \   }
+    \ ]
+    \})
+
+  AssertEqual g:handle_code_action_called, 1
+  AssertEqual
+  \ [
+  \   {
+  \     'description': 'codefix',
+  \     'changes': [
+  \       {
+  \         'fileName': "/foo/bar/file1.ts",
+  \         'textChanges': [
+  \           {
+  \             'end': {
+  \               'line': 2,
+  \               'offset': 1
+  \             },
+  \             'newText': 'import x from "./z";^@',
+  \             'start': {
+  \               'line': 2,
+  \               'offset': 1
+  \             }
+  \           }
+  \         ]
+  \       }
+  \     ]
+  \   }
+  \ ],
+  \ g:code_actions
+
+Execute(getCodeFixes from tsserver should be handled with user input if there are more than one action):
+  call ale#codefix#SetMap({3: {}})
+  call ale#codefix#HandleTSServerResponse(1, {
+    \ 'command': 'getCodeFixes',
+    \ 'request_seq': 3,
+    \ 'success': v:true,
+    \ 'type': 'response',
+    \ 'body': [
+    \   {
+    \     'description': 'Import default "x" from module "./z"',
+    \     'fixName': 'import',
+    \     'changes': [
+    \       {
+    \         'fileName': "/foo/bar/file1.ts",
+    \         'textChanges': [
+    \           {
+    \             'end': {
+    \               'line': 2,
+    \               'offset': 1,
+    \             },
+    \             'newText': 'import x from "./z";^@',
+    \             'start': {
+    \               'line': 2,
+    \               'offset': 1,
+    \             }
+    \           }
+    \         ]
+    \       }
+    \     ]
+    \   },
+    \   {
+    \     'description': 'Import default "x" from module "./y"',
+    \     'fixName': 'import',
+    \     'changes': [
+    \       {
+    \         'fileName': "/foo/bar/file1.ts",
+    \         'textChanges': [
+    \           {
+    \             'end': {
+    \               'line': 2,
+    \               'offset': 1,
+    \             },
+    \             'newText': 'import x from "./y";^@',
+    \             'start': {
+    \               'line': 2,
+    \               'offset': 1,
+    \             }
+    \           }
+    \         ]
+    \       }
+    \     ]
+    \   }
+    \ ]
+    \})
+
+  AssertEqual g:handle_code_action_called, 1
+  AssertEqual
+  \ [
+  \   {
+  \     'description': 'codefix',
+  \     'changes': [
+  \       {
+  \         'fileName': "/foo/bar/file1.ts",
+  \         'textChanges': [
+  \           {
+  \             'end': {
+  \               'line': 2,
+  \               'offset': 1
+  \             },
+  \             'newText': 'import x from "./y";^@',
+  \             'start': {
+  \               'line': 2,
+  \               'offset': 1
+  \             }
+  \           }
+  \         ]
+  \       }
+  \     ]
+  \   }
+  \ ],
+  \ g:code_actions
+
+Execute(Prints a tsserver error message when getCodeFixes unsuccessful):
+  call ale#codefix#SetMap({3: {}})
+  call ale#codefix#HandleTSServerResponse(1, {
+  \ 'command': 'getCodeFixes',
+  \ 'request_seq': 3,
+  \ 'success': v:false,
+  \ 'message': 'something is wrong',
+  \})
+
+  AssertEqual g:handle_code_action_called, 0
+  AssertEqual ['echom ''Error while getting code fixes. Reason: something is wrong'''], g:expr_list
+
+Execute(Does nothing when where are no code fixes):
+  call ale#codefix#SetMap({3: {}})
+  call ale#codefix#HandleTSServerResponse(1, {
+  \ 'command': 'getCodeFixes',
+  \ 'request_seq': 3,
+  \ 'success': v:true,
+  \ 'body': []
+  \})
+
+  AssertEqual g:handle_code_action_called, 0
+  AssertEqual ['echom ''No code fixes available.'''], g:expr_list
+
+Execute(tsserver codefix requests should be sent):
+  call ale#linter#Reset()
+
+  runtime ale_linters/typescript/tsserver.vim
+  let g:ale_buffer_info = {bufnr(''): {'loclist': [{'lnum': 2, 'col': 5, 'code': 2304}]}}
+  call setpos('.', [bufnr(''), 2, 5, 0])
+
+  " ALECodeAction
+  call ale#codefix#Execute(0)
+
+  " We shouldn't register the callback yet.
+  AssertEqual '''''', string(g:Callback)
+
+  AssertEqual type(function('type')), type(g:InitCallback)
+  call g:InitCallback()
+
+  AssertEqual 'code_actions', g:capability_checked
+  AssertEqual
+  \ 'function(''ale#codefix#HandleTSServerResponse'')',
+  \ string(g:Callback)
+  AssertEqual
+  \ [
+  \   ale#lsp#tsserver_message#Change(bufnr('')),
+  \   [0, 'ts@getCodeFixes', {
+  \     'startLine': 2,
+  \     'startOffset': 5,
+  \     'endLine': 2,
+  \     'endOffset': 6,
+  \     'file': expand('%:p'),
+  \     'errorCodes': [2304],
+  \   }]
+  \ ],
+  \ g:message_list
+
+Execute(tsserver codefix requests should be sent only for error with code):
+  call ale#linter#Reset()
+
+  runtime ale_linters/typescript/tsserver.vim
+  let g:ale_buffer_info = {bufnr(''): {'loclist': [{'lnum': 2, 'col': 5}, {'lnum': 2, 'col': 5, 'code': 2304}]}}
+  call setpos('.', [bufnr(''), 2, 5, 0])
+
+  " ALECodeAction
+  call ale#codefix#Execute(0)
+
+  " We shouldn't register the callback yet.
+  AssertEqual '''''', string(g:Callback)
+
+  AssertEqual type(function('type')), type(g:InitCallback)
+  call g:InitCallback()
+
+  AssertEqual 'code_actions', g:capability_checked
+  AssertEqual
+  \ 'function(''ale#codefix#HandleTSServerResponse'')',
+  \ string(g:Callback)
+  AssertEqual
+  \ [
+  \   ale#lsp#tsserver_message#Change(bufnr('')),
+  \   [0, 'ts@getCodeFixes', {
+  \     'startLine': 2,
+  \     'startOffset': 5,
+  \     'endLine': 2,
+  \     'endOffset': 6,
+  \     'file': expand('%:p'),
+  \     'errorCodes': [2304],
+  \   }]
+  \ ],
+  \ g:message_list
+
+Execute(getApplicableRefactors from tsserver should be handled):
+  call ale#codefix#SetMap({3: {
+  \ 'buffer': expand('%:p'),
+  \ 'line': 1,
+  \ 'column': 2,
+  \ 'end_line': 3,
+  \ 'end_column': 4,
+  \ 'connection_id': 0,
+  \}})
+  call ale#codefix#HandleTSServerResponse(1,
+  \ {'seq': 0, 'request_seq': 3, 'type': 'response', 'success': v:true, 'body': [{'actions': [{'description': 'Extract to constant in enclosing scope', 'name': 'constant_scope_0'}], 'description': 'Extract constant', 'name': 'Extract Symbol'}, {'actions': [{'description': 'Extract to function in module scope', 'name': 'function_scope_1'}], 'description': 'Extract function', 'name': 'Extract Symbol'}], 'command': 'getApplicableRefactors'})
+
+  AssertEqual
+  \ [
+  \   [0, 'ts@getEditsForRefactor', {
+  \     'startLine': 1,
+  \     'startOffset': 2,
+  \     'endLine': 3,
+  \     'endOffset': 5,
+  \     'file': expand('%:p'),
+  \     'refactor': 'Extract Symbol',
+  \     'action': 'function_scope_1',
+  \   }]
+  \ ],
+  \ g:message_list
+
+Execute(getApplicableRefactors should print error on failure):
+  call ale#codefix#SetMap({3: {
+  \ 'buffer': expand('%:p'),
+  \ 'line': 1,
+  \ 'column': 2,
+  \ 'end_line': 3,
+  \ 'end_column': 4,
+  \ 'connection_id': 0,
+  \}})
+  call ale#codefix#HandleTSServerResponse(1,
+  \ {'seq': 0, 'request_seq': 3, 'type': 'response', 'success': v:false, 'message': 'oops', 'command': 'getApplicableRefactors'})
+
+  AssertEqual ['echom ''Error while getting applicable refactors. Reason: oops'''], g:expr_list
+
+Execute(getApplicableRefactors should do nothing if there are no refactors):
+  call ale#codefix#SetMap({3: {
+  \ 'buffer': expand('%:p'),
+  \ 'line': 1,
+  \ 'column': 2,
+  \ 'end_line': 3,
+  \ 'end_column': 4,
+  \ 'connection_id': 0,
+  \}})
+  call ale#codefix#HandleTSServerResponse(1,
+  \ {'seq': 0, 'request_seq': 3, 'type': 'response', 'success': v:true, 'body': [], 'command': 'getApplicableRefactors'})
+
+  AssertEqual ['echom ''No applicable refactors available.'''], g:expr_list
+
+Execute(getEditsForRefactor from tsserver should be handled):
+  call ale#codefix#SetMap({3: {}})
+  call ale#codefix#HandleTSServerResponse(1,
+  \{'seq': 0, 'request_seq': 3, 'type': 'response', 'success': v:true, 'body': {'edits': [{'fileName': '/foo/bar/file.ts', 'textChanges': [{'end': {'offset': 35, 'line': 9}, 'newText': 'newFunction(app);', 'start': {'offset': 3, 'line': 8}}, {'end': {'offset': 4, 'line': 19}, 'newText': '^@function newFunction(app: Router) {^@    app.use(booExpressCsrf());^@    app.use(booExpressRequireHttps);^@}^@', 'start': {'offset': 4, 'line': 19}}]}], 'renameLocation': {'offset': 3, 'line': 8}, 'renameFilename': '/foo/bar/file.ts'}, 'command': 'getEditsForRefactor' }
+  \)
+
+  AssertEqual g:handle_code_action_called, 1
+  AssertEqual
+  \ [
+  \   {
+  \     'description': 'editsForRefactor',
+  \     'changes': [{'fileName': '/foo/bar/file.ts', 'textChanges': [{'end': {'offset': 35, 'line': 9}, 'newText': 'newFunction(app);', 'start': {'offset': 3, 'line': 8}}, {'end': {'offset': 4, 'line': 19}, 'newText': '^@function newFunction(app: Router) {^@    app.use(booExpressCsrf());^@    app.use(booExpressRequireHttps);^@}^@', 'start': {'offset': 4, 'line': 19}}]}],
+  \   }
+  \ ],
+  \ g:code_actions
+
+Execute(getEditsForRefactor should print error on failure):
+  call ale#codefix#SetMap({3: {}})
+  call ale#codefix#HandleTSServerResponse(1,
+  \{'seq': 0, 'request_seq': 3, 'type': 'response', 'success': v:false, 'message': 'oops', 'command': 'getEditsForRefactor' }
+  \)
+
+  AssertEqual ['echom ''Error while getting edits for refactor. Reason: oops'''], g:expr_list
+
+" TODO: I can't figure out how to run ALECodeAction on range
+" in test function. Therefore I can't write properly working
+" test. If somebody knows how to do that help is appreciated.
+"
+" Execute(tsserver getApplicableRefactors requests should be sent):
+"   call ale#linter#Reset()
+"
+"   runtime ale_linters/typescript/tsserver.vim
+"   let g:ale_buffer_info = {bufnr(''): {'loclist': []}}
+"   call setpos('.', [bufnr(''), 2, 5, 0])
+"   normal "v$"
+"
+"   execute "ALECodeAction"
+"
+"   " We shouldn't register the callback yet.
+"   AssertEqual '''''', string(g:Callback)
+"
+"   AssertEqual type(function('type')), type(g:InitCallback)
+"   call g:InitCallback()
+"
+"   AssertEqual 'code_actions', g:capability_checked
+"   AssertEqual
+"   \ 'function(''ale#codefix#HandleTSServerResponse'')',
+"   \ string(g:Callback)
+"   AssertEqual
+"   \ [
+"   \   ale#lsp#tsserver_message#Change(bufnr('')),
+"   \   [0, 'ts@getApplicableRefactors', {
+"   \     'startLine': 2,
+"   \     'startOffset': 5,
+"   \     'endLine': 2,
+"   \     'endOffset': 15,
+"   \     'file': expand('%:p'),
+"   \   }]
+"   \ ],
+"   \ g:message_list
+
+Execute(Failed LSP responses should be handled correctly):
+  call ale#codefix#HandleLSPResponse(
+  \ 1,
+  \ {'method': 'workspace/applyEdit', 'request_seq': 3}
+  \)
+  AssertEqual g:handle_code_action_called, 0
+
+Given python(Some python file):
+  def main():
+      a = 1
+      b = a + 2
+
+Execute("workspace/applyEdit" from LSP should be handled):
+  call ale#codefix#SetMap({3: {}})
+  call ale#codefix#HandleLSPResponse(1,
+  \ {'id': 0, 'jsonrpc': '2.0', 'method': 'workspace/applyEdit', 'params': {'edit': {'changes': {'file:///foo/bar/file.ts': [{'range': {'end': {'character': 27, 'line': 7}, 'start': {'character': 27, 'line': 7}}, 'newText': ', Config'}, {'range': {'end': {'character': 12, 'line': 96}, 'start': {'character': 2, 'line': 94}}, 'newText': 'await newFunction(redis, imageKey, cover, config);'}, {'range': {'end': {'character': 2, 'line': 99}, 'start': {'character': 2, 'line': 99}}, 'newText': '^@async function newFunction(redis: IRedis, imageKey: string, cover: Buffer, config: Config) {^@    try {^@        await redis.set(imageKey, cover, ''ex'', parseInt(config.coverKeyTTL, 10));^@    }^@    catch { }^@}^@'}]}}}})
+
+  AssertEqual g:handle_code_action_called, 1
+  AssertEqual
+  \ [{'description': 'applyEdit', 'changes': [{'fileName': '/foo/bar/file.ts', 'textChanges': [{'end': {'offset': 28, 'line': 8}, 'newText': ', Config', 'start': {'offset': 28, 'line': 8}}, {'end': {'offset': 13, 'line': 97}, 'newText': 'await newFunction(redis, imageKey, cover, config);', 'start': {'offset': 3, 'line': 95}}, {'end': {'offset': 3, 'line': 100}, 'newText': '^@async function newFunction(redis: IRedis, imageKey: string, cover: Buffer, config: Config) {^@    try {^@        await redis.set(imageKey, cover, ''ex'', parseInt(config.coverKeyTTL, 10));^@    }^@    catch { }^@}^@', 'start': {'offset': 3, 'line': 100}}]}]}],
+  \ g:code_actions
+
+Execute(Code Actions from LSP should be handled with user input if there are more than one action):
+  call ale#codefix#SetMap({2: {}})
+  call ale#codefix#HandleLSPResponse(1,
+  \ {'id': 2, 'jsonrpc': '2.0', 'result': [{'title': 'fake for testing'}, {'arguments': [{'documentChanges': [{'edits': [{'range': {'end': {'character': 31, 'line': 2}, 'start': {'character': 31, 'line': 2}}, 'newText': ', createVideo'}], 'textDocument': {'uri': 'file:///foo/bar/file.ts', 'version': 1}}]}], 'title': 'Add ''createVideo'' to existing import declaration from "./video"', 'command': '_typescript.applyWorkspaceEdit'}]})
+
+  AssertEqual g:handle_code_action_called, 1
+  AssertEqual
+  \ [{'description': 'codeaction', 'changes': [{'fileName': '/foo/bar/file.ts', 'textChanges': [{'end': {'offset': 32, 'line': 3}, 'newText': ', createVideo', 'start': {'offset': 32, 'line': 3}}]}]}],
+  \ g:code_actions
+
+Execute(Code Actions from LSP should be handled when returned with documentChanges):
+  call ale#codefix#SetMap({2: {}})
+  call ale#codefix#HandleLSPResponse(1,
+  \ {'id': 2, 'jsonrpc': '2.0', 'result': [{'diagnostics': v:null, 'edit': {'changes': v:null, 'documentChanges': [{'edits': [{'range': {'end': {'character': 4, 'line': 2}, 'start': {'character': 4, 'line': 1}}, 'newText': ''}, {'range': {'end': {'character': 9, 'line': 2}, 'start': {'character': 8, 'line': 2}}, 'newText': '(1)'}], 'textDocument': {'uri': 'file:///foo/bar/test.py', 'version': v:null}}]}, 'kind': 'refactor.inline', 'title': 'Inline variable', 'command': v:null}, {'diagnostics': v:null, 'edit': {'changes': v:null, 'documentChanges': [{'edits': [{'range': {'end': {'character': 0, 'line': 0}, 'start': {'character': 0, 'line': 0}}, 'newText': 'def func_bomdjnxh():^@    a = 1return a^@^@^@'}, {'range': {'end': {'character': 9, 'line': 1}, 'start': {'character': 8, 'line': 1}}, 'newText': 'func_bomdjnxh()^@'}], 'textDocument': {'uri': 'file:///foo/bar/test.py', 'version': v:null}}]}, 'kind': 'refactor.extract', 'title': 'Extract expression into function ''func_bomdjnxh''', 'command': v:null}]})
+
+  AssertEqual g:handle_code_action_called, 1
+  AssertEqual
+  \ [{'description': 'codeaction', 'changes': [{'fileName': '/foo/bar/test.py', 'textChanges': [{'end': {'offset': 1, 'line': 1}, 'newText': 'def func_bomdjnxh():^@    a = 1return a^@^@^@', 'start': {'offset': 1, 'line': 1}}, {'end': {'offset': 10, 'line': 2}, 'newText': 'func_bomdjnxh()^@', 'start': {'offset': 9, 'line': 2}}]}]}],
+  \ g:code_actions
+
+Execute(LSP Code Actions handles command responses):
+  call ale#codefix#SetMap({3: {
+  \ 'connection_id': 0,
+  \}})
+  call ale#codefix#HandleLSPResponse(1,
+  \ {'id': 3, 'jsonrpc': '2.0', 'result': [{'kind': 'refactor', 'title': 'Extract to inner function in function ''getVideo''', 'command': {'arguments': [{'file': '/foo/bar/file.ts', 'endOffset': 0, 'action': 'function_scope_0', 'startOffset': 1, 'startLine': 65, 'refactor': 'Extract Symbol', 'endLine': 68}], 'title': 'Extract to inner function in function ''getVideo''', 'command': '_typescript.applyRefactoring'}}, {'kind': 'refactor', 'title': 'Extract to function in module scope', 'command': {'arguments': [{'file': '/foo/bar/file.ts', 'endOffset': 0, 'action': 'function_scope_1', 'startOffset': 1, 'startLine': 65, 'refactor': 'Extract Symbol', 'endLine': 68}], 'title': 'Extract to function in module scope', 'command': '_typescript.applyRefactoring'}}]})
+
+  AssertEqual
+  \ [[0, 'workspace/executeCommand', {'arguments': [{'file': '/foo/bar/file.ts', 'action': 'function_scope_1', 'endOffset': 0, 'refactor': 'Extract Symbol', 'endLine': 68, 'startLine': 65, 'startOffset': 1}], 'command': '_typescript.applyRefactoring'}]],
+  \ g:message_list
+
+
+Execute(Prints message when LSP code action returns no results):
+  call ale#codefix#SetMap({3: {}})
+  call ale#codefix#HandleLSPResponse(1,
+  \ {'id': 3, 'jsonrpc': '2.0', 'result': []})
+
+  AssertEqual g:handle_code_action_called, 0
+  AssertEqual ['echom ''No code actions received from server'''], g:expr_list
+
+Execute(LSP code action requests should be sent):
+  call ale#linter#Reset()
+
+  runtime ale_linters/python/jedils.vim
+  let g:ale_buffer_info = {bufnr(''): {'loclist': [{'lnum': 2, 'col': 5, 'end_lnum': 2, 'end_col': 6, 'code': 2304, 'text': 'oops'}]}}
+  call setpos('.', [bufnr(''), 2, 5, 0])
+
+  " ALECodeAction
+  call ale#codefix#Execute(0)
+
+  " We shouldn't register the callback yet.
+  AssertEqual '''''', string(g:Callback)
+
+  AssertEqual type(function('type')), type(g:InitCallback)
+  call g:InitCallback()
+
+  AssertEqual 'code_actions', g:capability_checked
+  AssertEqual
+  \ 'function(''ale#codefix#HandleLSPResponse'')',
+  \ string(g:Callback)
+  AssertEqual
+  \ [
+  \   [1, 'workspace/didChangeConfiguration', {'settings': {'python': {}}}],
+  \   [1, 'textDocument/didChange', {
+  \     'contentChanges': [{'text': "def main():\n    a = 1\n    b = a + 2\n"}],
+  \     'textDocument': {
+  \         'uri': ale#path#ToURI(expand('%:p')),
+  \         'version': g:ale_lsp_next_version_id - 1,
+  \     },
+  \   }],
+  \   [0, 'textDocument/codeAction', {
+  \     'context': {
+  \       'diagnostics': [{'range': {'end': {'character': 5, 'line': 1}, 'start': {'character': 4, 'line': 1}}, 'code': 2304, 'message': 'oops'}]
+  \     },
+  \     'range': {'end': {'character': 5, 'line': 1}, 'start': {'character': 4, 'line': 1}},
+  \     'textDocument': {'uri': ale#path#ToURI(expand('%:p'))}
+  \   }]
+  \ ],
+  \ g:message_list
+
+Execute(LSP code action requests should be sent only for error with code):
+  call ale#linter#Reset()
+
+  runtime ale_linters/python/jedils.vim
+  let g:ale_buffer_info = {bufnr(''): {'loclist': [{'lnum': 2, 'col': 5, 'end_lnum': 2, 'end_col': 6, 'code': 2304, 'text': 'oops'}]}}
+  call setpos('.', [bufnr(''), 2, 5, 0])
+
+  " ALECodeAction
+  call ale#codefix#Execute(0)
+
+  " We shouldn't register the callback yet.
+  AssertEqual '''''', string(g:Callback)
+
+  AssertEqual type(function('type')), type(g:InitCallback)
+  call g:InitCallback()
+
+  AssertEqual 'code_actions', g:capability_checked
+  AssertEqual
+  \ 'function(''ale#codefix#HandleLSPResponse'')',
+  \ string(g:Callback)
+  AssertEqual
+  \ [
+  \   [1, 'workspace/didChangeConfiguration', {'settings': {'python': {}}}],
+  \   [1, 'textDocument/didChange', {
+  \     'contentChanges': [{'text': "def main():\n    a = 1\n    b = a + 2\n"}],
+  \     'textDocument': {
+  \         'uri': ale#path#ToURI(expand('%:p')),
+  \         'version': g:ale_lsp_next_version_id - 1,
+  \     },
+  \   }],
+  \   [0, 'textDocument/codeAction', {
+  \     'context': {
+  \       'diagnostics': [{'range': {'end': {'character': 5, 'line': 1}, 'start': {'character': 4, 'line': 1}}, 'code': 2304, 'message': 'oops'}]
+  \     },
+  \     'range': {'end': {'character': 5, 'line': 1}, 'start': {'character': 4, 'line': 1}},
+  \     'textDocument': {'uri': ale#path#ToURI(expand('%:p'))}
+  \   }]
+  \ ],
+  \ g:message_list