LSP/completion: Add completion text helper function

1 files changed, 14 insertions, 2 deletions

diff --git a/runtime/lua/vim/lsp/util.lua b/runtime/lua/vim/lsp/util.lua
index 533bcf2779..5217464c22 100644
--- a/runtime/lua/vim/lsp/util.lua
+++ b/runtime/lua/vim/lsp/util.lua
@@ -157,11 +157,23 @@ local function sort_completion_items(items)
   end
 end
 
+-- Returns text that should be inserted when selecting completion item. The precedence is as follows:
+-- textEdit.newText > insertText > label
+-- https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textDocument_completion
+local function get_completion_word(item)
+  if item.textEdit ~= nil and item.textEdit.newText ~= nil then
+    return item.textEdit.newText
+  elseif item.insertText ~= nil then
+    return item.insertText
+  end
+  return item.label
+end
+
 -- Some lanuguage servers return complementary candidates whose prefixes do not match are also returned.
 -- So we exclude completion candidates whose prefix does not match.
 local function remove_unmatch_completion_items(items, prefix)
   return vim.tbl_filter(function(item)
-    local word = (item.textEdit and item.textEdit.newText) or item.insertText or item.label
+    local word = get_completion_word(item)
     return vim.startswith(word, prefix)
   end, items)
 end
@@ -193,7 +205,7 @@ function M.text_document_completion_list_to_complete_items(result, prefix)
       end
     end
 
-    local word = (completion_item.textEdit and completion_item.textEdit.newText) or completion_item.insertText or completion_item.label
+    local word = get_completion_word(completion_item)
     table.insert(matches, {
       word = word,
       abbr = completion_item.label,