perf: avoid global completion in component start tag

.changeset/bumpy-buttons-prove.md

@@ -0,0 +1,5 @@
+---
+'svelte-language-server': patch
+---
+
+perf: avoid global completion in component start tag

packages/language-server/src/plugins/typescript/features/CompletionProvider.ts

@@ -74,6 +74,8 @@ interface CommitCharactersOptions {
     isNewIdentifierLocation?: boolean;
 }
 
+const ENSURE_COMPONENT_HELPER = '__sveltets_2_ensureComponent';
+
 export class CompletionsProviderImpl implements CompletionsProvider<CompletionResolveInfo> {
     constructor(
         private readonly lsAndTsDocResolver: LSAndTSDocResolver,
@@ -249,20 +251,32 @@ export class CompletionsProviderImpl implements CompletionsProvider<CompletionRe
         ) {
             const name = svelteNode.name;
             const nameEnd = svelteNode.start + 1 + name.length;
-            const isWhitespaceAfterStartTag =
-                document.getText().slice(nameEnd, originalOffset).trim() === '' &&
-                this.mightBeAtStartTagWhitespace(document, originalOffset);
-
-            if (isWhitespaceAfterStartTag) {
-                // We can be sure only to get completions for directives and props here
-                // so don't bother with the expensive global completions
-                return this.getCompletionListForDirectiveOrProps(
-                    attributeContext,
-                    componentInfo,
-                    wordInfo.defaultTextEditRange,
-                    eventAndSlotLetCompletions,
-                    tsDoc
-                );
+            const mightBeAtStartTagWhitespace = this.mightBeAtStartTagWhitespace(
+                document,
+                originalOffset
+            );
+
+            const generatedText = tsDoc.getFullText();
+            if (mightBeAtStartTagWhitespace && originalOffset > nameEnd) {
+                // If it's in whitespace after the component name in the start tag,
+                // this should trigger only directive and prop completions
+                // Unless it's correctly mapped to props. Handle it by ourselves to avoid expensive global completions
+                if (!generatedText.slice(0, offset).endsWith('props: {')) {
+                    return this.getCompletionListForDirectiveOrProps(
+                        attributeContext,
+                        componentInfo,
+                        wordInfo.defaultTextEditRange,
+                        eventAndSlotLetCompletions,
+                        tsDoc
+                    );
+                }
+            } else {
+                const componentNameOffByOne = generatedText
+                    .slice(0, offset + 1)
+                    .endsWith(ENSURE_COMPONENT_HELPER + '(' + name);
+                if (componentNameOffByOne) {
+                    offset++;
+                }
             }
         }
 

packages/language-server/test/plugins/typescript/features/CompletionProvider.test.ts

@@ -1880,4 +1880,50 @@ describe('CompletionProviderImpl', function () {
         const item = completions?.items.find((item) => item.label === 'hi');
         assert.ok(item);
     });
+
+    it('provides namespace component completions for Svelte 5+', async () => {
+        const { completionProvider, document } = setup('namespaced-v5.svelte');
+
+        const completions = await completionProvider.getCompletions(
+            document,
+            Position.create(4, 12),
+            {
+                triggerKind: CompletionTriggerKind.Invoked
+            }
+        );
+
+        const item = completions?.items.find((item) => item.label === 'ComponentDef');
+        assert.ok(item);
+    });
+
+    it('use correct position for component tag auto-import', async () => {
+        const { completionProvider, document } = setup('importcompletions_unclose-tag.svelte');
+
+        const completionsAssumption = await completionProvider.getCompletions(
+            document,
+            Position.create(0, 4)
+        );
+
+        const itemAssumption = completionsAssumption?.items.find(
+            (item) => item.label === 'Completions'
+        );
+        assert.ok(
+            itemAssumption,
+            `expected this to exist. Otherwise, the "Completions" assertion is wrong`
+        );
+
+        const completions = await completionProvider.getCompletions(
+            document,
+            Position.create(1, 2)
+        );
+
+        const item = completions?.items.find((item) => item.label === 'EmptytextImported');
+        assert.ok(item);
+
+        const shouldNotExistItem = completions?.items.find((item) => item.label === 'Completions');
+        assert.ok(
+            !shouldNotExistItem,
+            'expected auto-import be filtered out by current identifier'
+        );
+    });
 });

packages/language-server/test/plugins/typescript/testfiles/completions/importcompletions_unclose-tag.svelte

@@ -0,0 +1,2 @@
+<Com />
+<E

packages/language-server/test/plugins/typescript/testfiles/completions/namespaced-v5.svelte

@@ -0,0 +1,5 @@
+<script lang="ts">
+    import * as Components from './ComponentDef'
+</script>
+
+<Components.