Refactor ghost text logic to correctly check for whitespace or end-of-input after the caret before suggesting completions

Author: robertpiosik

packages/ui/src/components/editor/panel/PromptField/hooks/use-ghost-text.ts

@@ -65,25 +65,32 @@ export const use_ghost_text = ({
       if (selection && selection.rangeCount > 0) {
         const range = selection.getRangeAt(0)
         if (range.collapsed) {
-          const pre_caret_range = range.cloneRange()
-          pre_caret_range.selectNodeContents(input_ref.current)
-          pre_caret_range.setEnd(range.startContainer, range.startOffset)
-          const text_before_cursor = pre_caret_range.toString()
-          const last_word_match = text_before_cursor.match(/[\S]+$/)
-
-          if (last_word_match) {
-            const last_word_with_prefix = last_word_match[0]
-            const word_start_match =
-              last_word_with_prefix.match(/[a-zA-Z_]/)
-            if (word_start_match) {
-              const last_word = last_word_with_prefix.substring(
-                word_start_match.index ?? 0
-              )
-              if (last_word.length >= 2) {
-                for (const id of identifiers) {
-                  if (id.startsWith(last_word) && id !== last_word) {
-                    potential_ghost_text = id.substring(last_word.length)
-                    break
+          const post_caret_range = range.cloneRange()
+          post_caret_range.selectNodeContents(input_ref.current)
+          post_caret_range.setStart(range.endContainer, range.endOffset)
+          const text_after_cursor = post_caret_range.toString()
+
+          if (text_after_cursor === '' || /^\s/.test(text_after_cursor)) {
+            const pre_caret_range = range.cloneRange()
+            pre_caret_range.selectNodeContents(input_ref.current)
+            pre_caret_range.setEnd(range.startContainer, range.startOffset)
+            const text_before_cursor = pre_caret_range.toString()
+            const last_word_match = text_before_cursor.match(/[\S]+$/)
+
+            if (last_word_match) {
+              const last_word_with_prefix = last_word_match[0]
+              const word_start_match =
+                last_word_with_prefix.match(/[a-zA-Z_]/)
+              if (word_start_match) {
+                const last_word = last_word_with_prefix.substring(
+                  word_start_match.index ?? 0
+                )
+                if (last_word.length >= 2) {
+                  for (const id of identifiers) {
+                    if (id.startsWith(last_word) && id !== last_word) {
+                      potential_ghost_text = id.substring(last_word.length)
+                      break
+                    }
                   }
                 }
               }