diff --git a/lua/config/util.lua b/lua/config/util.lua
index bd0d748..af917c6 100644
--- a/lua/config/util.lua
+++ b/lua/config/util.lua
@@ -1,3 +1,27 @@
+local function invoke(args)
+    output = vim.fn.system(table.concat(args, ' '))
+    return string.gsub(output, '%s+$', '')
+end
+
+local function get_branch_parent()
+    local author = invoke({'git', 'config', 'user.name'})
+
+    local hash = invoke{
+        'git',
+        'log',
+        '-n1',
+        '--author="^((?!' .. author .. ').)*$"',
+        '--perl-regexp',
+        '--pretty=format:"%H"'
+    }
+
+    if #hash == 0 then
+        print('All commits are by current author')
+    else
+        return hash
+    end
+end
+
 -- UnAlign
 vim.api.nvim_create_user_command(
     'UnAlign',
@@ -7,32 +31,33 @@ vim.api.nvim_create_user_command(
     {range = '%'}
 )
 
--- GitStreak
+-- TopicEdit
 vim.api.nvim_create_user_command(
-    'GitStreak',
+    'TopicEdit',
     function(ctx)
-        local function call(args)
-            output = vim.fn.system(table.concat(args, ' '))
-            return string.gsub(output, '%s+$', '')
-        end
-
-        local root_dir = call({'git', 'rev-parse', '--show-toplevel'})
-        local author = call({'git', 'config', 'user.name'})
-
-        local hash = call{'git', 'log', '-n1', '--author="^((?!' .. author .. ').)*$"', '--perl-regexp', '--pretty=format:"%H"'}
-        if #hash == 0 then
-            print('All commits are by current author')
-            return
-        end
-
-        local names = call({'git', 'diff', '--name-only', hash})
-        if #names == 0 then
-            print('No files changed since previous author')
-            return
-        end
-
-        for name in string.gmatch(names, '[^\r\n]+') do
-            vim.cmd(string.format('e %s/%s', root_dir, name))
+        local hash = get_branch_parent()
+        if hash then
+            local names = invoke({'git', 'diff', '--name-only', hash})
+            if #names == 0 then
+                print('No files changed since previous author')
+            else
+                local root_dir = invoke({'git', 'rev-parse', '--show-toplevel'})
+                for name in string.gmatch(names, '[^\r\n]+') do
+                    vim.cmd(string.format('e %s/%s', root_dir, name))
+                end
+            end
+        end
+    end,
+    {}
+)
+
+-- TopicDiff
+vim.api.nvim_create_user_command(
+    'TopicDiff',
+    function(ctx)
+        local hash = get_branch_parent()
+        if hash then
+            invoke({'git', 'difftool', '-d', hash})
         end
     end,
     {}