feat: Svelte 5 component class/function interop

packages/language-server/src/plugins/typescript/ComponentInfoProvider.ts

@@ -95,7 +95,12 @@ export class JsOrTsComponentInfoProvider implements ComponentInfoProvider {
             return null;
         }
 
-        const defClass = findContainingNode(sourceFile, def.textSpan, ts.isClassDeclaration);
+        const defClass = findContainingNode(
+            sourceFile,
+            def.textSpan,
+            (node): node is ts.ClassDeclaration | ts.VariableDeclaration =>
+                ts.isClassDeclaration(node) || ts.isTypeAliasDeclaration(node)
+        );
 
         if (!defClass) {
             return null;

packages/language-server/src/plugins/typescript/DocumentSnapshot.ts

@@ -268,6 +268,7 @@ export class SvelteDocumentSnapshot implements DocumentSnapshot {
     private url = pathToUrl(this.filePath);
 
     version = this.parent.version;
+    isSvelte5Plus = Number(this.svelteVersion?.split('.')[0]) >= 5;
 
     constructor(
         public readonly parent: Document,
@@ -281,10 +282,6 @@ export class SvelteDocumentSnapshot implements DocumentSnapshot {
         private readonly htmlAst?: TemplateNode
     ) {}
 
-    get isSvelte5Plus() {
-        return Number(this.svelteVersion?.split('.')[0]) >= 5;
-    }
-
     get filePath() {
         return this.parent.getFilePath() || '';
     }

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

@@ -851,7 +851,7 @@ export class CompletionsProviderImpl implements CompletionsProvider<CompletionRe
 
         if (detail) {
             const { detail: itemDetail, documentation: itemDocumentation } =
-                this.getCompletionDocument(detail, is$typeImport);
+                this.getCompletionDocument(tsDoc, detail, is$typeImport);
 
             // VSCode + tsserver won't have this pop-in effect
             // because tsserver has internal APIs for caching
@@ -897,7 +897,11 @@ export class CompletionsProviderImpl implements CompletionsProvider<CompletionRe
         return completionItem;
     }
 
-    private getCompletionDocument(compDetail: ts.CompletionEntryDetails, is$typeImport: boolean) {
+    private getCompletionDocument(
+        tsDoc: SvelteDocumentSnapshot,
+        compDetail: ts.CompletionEntryDetails,
+        is$typeImport: boolean
+    ) {
         const { sourceDisplay, documentation: tsDocumentation, displayParts, tags } = compDetail;
         let parts = compDetail.codeActions?.map((codeAction) => codeAction.description) ?? [];
 
@@ -910,7 +914,16 @@ export class CompletionsProviderImpl implements CompletionsProvider<CompletionRe
             );
         }
 
-        parts.push(changeSvelteComponentName(ts.displayPartsToString(displayParts)));
+        let text = changeSvelteComponentName(ts.displayPartsToString(displayParts));
+        if (
+            tsDoc.isSvelte5Plus &&
+            text.includes('(alias)') &&
+            text.includes('__SvelteComponent_')
+        ) {
+            // The info contains both the const and type export along with a bunch of gibberish we want to hide
+            text = text.substring(0, text.indexOf('(alias)') - 1);
+        }
+        parts.push(text);
 
         const markdownDoc = getMarkdownDocumentation(tsDocumentation, tags);
         const documentation: MarkupContent | undefined = markdownDoc

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

@@ -167,7 +167,7 @@ export class DiagnosticsProviderImpl implements DiagnosticsProvider {
                 continue;
             }
 
-            diagnostic = adjustIfNecessary(diagnostic);
+            diagnostic = adjustIfNecessary(diagnostic, tsDoc.isSvelte5Plus);
             diagnostic = swapDiagRangeStartEndIfNecessary(diagnostic);
             converted.push(diagnostic);
         }
@@ -350,7 +350,7 @@ function isNoUsedBeforeAssigned(
 /**
  * Some diagnostics have JSX-specific or confusing nomenclature. Enhance/adjust them for more clarity.
  */
-function adjustIfNecessary(diagnostic: Diagnostic): Diagnostic {
+function adjustIfNecessary(diagnostic: Diagnostic, isSvelte5Plus: boolean): Diagnostic {
     if (
         diagnostic.code === DiagnosticCode.ARG_TYPE_X_NOT_ASSIGNABLE_TO_TYPE_Y &&
         diagnostic.message.includes('ConstructorOfATypedSvelteComponent')
@@ -362,9 +362,11 @@ function adjustIfNecessary(diagnostic: Diagnostic): Diagnostic {
                 '\n\nPossible causes:\n' +
                 '- You use the instance type of a component where you should use the constructor type\n' +
                 '- Type definitions are missing for this Svelte Component. ' +
-                'If you are using Svelte 3.31+, use SvelteComponentTyped to add a definition:\n' +
-                '  import type { SvelteComponentTyped } from "svelte";\n' +
-                '  class ComponentName extends SvelteComponentTyped<{propertyName: string;}> {}'
+                (isSvelte5Plus
+                    ? ''
+                    : 'If you are using Svelte 3.31+, use SvelteComponentTyped to add a definition:\n' +
+                      '  import type { SvelteComponentTyped } from "svelte";\n' +
+                      '  class ComponentName extends SvelteComponentTyped<{propertyName: string;}> {}')
         };
     }
 

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

@@ -168,7 +168,26 @@ export class FindReferencesProviderImpl implements FindReferencesProvider {
             )
         );
 
-        return flatten(references.filter(isNotNullOrUndefined));
+        const flattened: Location[] = [];
+        for (const ref of references) {
+            if (ref) {
+                const tmp: Location[] = []; // perf optimization: we know each iteration has unique references
+                for (const r of ref) {
+                    const exists = flattened.some(
+                        (f) =>
+                            f.uri === r.uri &&
+                            f.range.start.line === r.range.start.line &&
+                            f.range.start.character === r.range.start.character
+                    );
+                    if (!exists) {
+                        tmp.push(r);
+                    }
+                }
+                flattened.push(...tmp);
+            }
+        }
+
+        return flattened;
     }
 
     private async mapReference(

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

@@ -50,21 +50,42 @@ export function getComponentAtPosition(
         doc.positionAt(node.start + symbolPosWithinNode + 1)
     );
 
-    let def = lang.getDefinitionAtPosition(tsDoc.filePath, tsDoc.offsetAt(generatedPosition))?.[0];
-
-    while (def != null && def.kind !== ts.ScriptElementKind.classElement) {
-        const newDef = lang.getDefinitionAtPosition(tsDoc.filePath, def.textSpan.start)?.[0];
-        if (newDef?.fileName === def.fileName && newDef?.textSpan.start === def.textSpan.start) {
+    let defs = lang.getDefinitionAtPosition(tsDoc.filePath, tsDoc.offsetAt(generatedPosition));
+    // Svelte 5 uses a const and a type alias instead of a class, and we want the latter.
+    // We still gotta check for a class in Svelte 5 because of d.ts files generated for Svelte 4 containing classes.
+    let def1 = defs?.[0];
+    let def2 = tsDoc.isSvelte5Plus ? defs?.[1] : undefined;
+
+    while (
+        def1 != null &&
+        def1.kind !== ts.ScriptElementKind.classElement &&
+        (def2 == null ||
+            def2.kind !== ts.ScriptElementKind.constElement ||
+            !def2.name.endsWith('__SvelteComponent_'))
+    ) {
+        const newDefs = lang.getDefinitionAtPosition(tsDoc.filePath, def1.textSpan.start);
+        const newDef = newDefs?.[0];
+        if (newDef?.fileName === def1.fileName && newDef?.textSpan.start === def1.textSpan.start) {
             break;
         }
-        def = newDef;
+        defs = newDefs;
+        def1 = newDef;
+        def2 = tsDoc.isSvelte5Plus ? newDefs?.[1] : undefined;
     }
 
-    if (!def) {
+    if (!def1 && !def2) {
         return null;
     }
 
-    return JsOrTsComponentInfoProvider.create(lang, def);
+    if (
+        def2 != null &&
+        def2.kind === ts.ScriptElementKind.constElement &&
+        def2.name.endsWith('__SvelteComponent_')
+    ) {
+        def1 = undefined;
+    }
+
+    return JsOrTsComponentInfoProvider.create(lang, def1! || def2!);
 }
 
 export function isComponentAtPosition(

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

@@ -14,8 +14,10 @@ import { LSAndTSDocResolver } from '../../../../src/plugins/typescript/LSAndTSDo
 import { __resetCache } from '../../../../src/plugins/typescript/service';
 import { pathToUrl } from '../../../../src/utils';
 import { serviceWarmup } from '../test-utils';
+import { VERSION } from 'svelte/compiler';
 
 const testDir = path.join(__dirname, '..');
+const isSvelte5Plus = +VERSION.split('.')[0] >= 5;
 
 describe('CallHierarchyProvider', function () {
     const callHierarchyTestDirRelative = path.join('testfiles', 'call-hierarchy');
@@ -386,6 +388,11 @@ describe('CallHierarchyProvider', function () {
     });
 
     it('can provide outgoing calls for component file', async () => {
+        if (isSvelte5Plus) {
+            // Doesn't work due to https://github.com/microsoft/TypeScript/issues/43740 and https://github.com/microsoft/TypeScript/issues/42375
+            return;
+        }
+
         const { provider, document } = setup(outgoingComponentName);
 
         const items = await provider.prepareCallHierarchy(document, { line: 10, character: 1 });
@@ -411,6 +418,11 @@ describe('CallHierarchyProvider', function () {
     });
 
     it('can provide outgoing calls for component tags', async () => {
+        if (isSvelte5Plus) {
+            // Doesn't work due to https://github.com/microsoft/TypeScript/issues/43740 and https://github.com/microsoft/TypeScript/issues/42375
+            return;
+        }
+
         const { provider, document } = setup(outgoingComponentName);
 
         const items = await provider.prepareCallHierarchy(document, { line: 0, character: 2 });

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

@@ -21,9 +21,11 @@ import { __resetCache } from '../../../../src/plugins/typescript/service';
 import { pathToUrl } from '../../../../src/utils';
 import { recursiveServiceWarmup } from '../test-utils';
 import { DiagnosticCode } from '../../../../src/plugins/typescript/features/DiagnosticsProvider';
+import { VERSION } from 'svelte/compiler';
 
 const testDir = path.join(__dirname, '..');
 const indent = ' '.repeat(4);
+const isSvelte5Plus = +VERSION.split('.')[0] >= 5;
 
 describe('CodeActionsProvider', function () {
     recursiveServiceWarmup(
@@ -374,6 +376,17 @@ describe('CodeActionsProvider', function () {
             uri: getUri('codeaction-checkJs.svelte'),
             version: null
         };
+
+        if (isSvelte5Plus) {
+            // Maybe because of the hidden interface declarations? It's harmless anyway
+            if (
+                codeActions.length === 4 &&
+                codeActions[3].title === "Add '@ts-ignore' to all error messages"
+            ) {
+                codeActions.splice(3, 1);
+            }
+        }
+
         assert.deepStrictEqual(codeActions, <CodeAction[]>[
             {
                 edit: {

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

@@ -24,11 +24,13 @@ import { sortBy } from 'lodash';
 import { LSConfigManager } from '../../../../src/ls-config';
 import { __resetCache } from '../../../../src/plugins/typescript/service';
 import { getRandomVirtualDirPath, serviceWarmup, setupVirtualEnvironment } from '../test-utils';
+import { VERSION } from 'svelte/compiler';
 
 const testDir = join(__dirname, '..');
 const testFilesDir = join(testDir, 'testfiles', 'completions');
 const newLine = ts.sys.newLine;
 const indent = ' '.repeat(4);
+const isSvelte5Plus = +VERSION.split('.')[0] >= 5;
 
 const fileNameToAbsoluteUri = (file: string) => {
     return pathToUrl(join(testFilesDir, file));
@@ -855,7 +857,7 @@ describe('CompletionProviderImpl', function () {
 
         assert.strictEqual(
             detail,
-            'Add import from "../imported-file.svelte"\n\nclass ImportedFile'
+            `Add import from "../imported-file.svelte"${isSvelte5Plus ? '' : '\n\nclass ImportedFile'}`
         );
 
         assert.strictEqual(
@@ -893,7 +895,7 @@ describe('CompletionProviderImpl', function () {
 
         assert.strictEqual(
             detail,
-            'Add import from "../imported-file.svelte"\n\nclass ImportedFile'
+            `Add import from "../imported-file.svelte"${isSvelte5Plus ? '' : '\n\nclass ImportedFile'}`
         );
 
         assert.strictEqual(
@@ -1502,7 +1504,10 @@ describe('CompletionProviderImpl', function () {
         const item2 = completions2?.items.find((item) => item.label === 'Bar');
         const { detail } = await completionProvider.resolveCompletion(document, item2!);
 
-        assert.strictEqual(detail, 'Add import from "./Bar.svelte"\n\nclass Bar');
+        assert.strictEqual(
+            detail,
+            `Add import from "./Bar.svelte"${isSvelte5Plus ? '' : '\n\nclass Bar'}`
+        );
     });
 
     it("doesn't use empty cache", async () => {
@@ -1551,7 +1556,10 @@ describe('CompletionProviderImpl', function () {
         const item2 = completions?.items.find((item) => item.label === 'Bar');
         const { detail } = await completionProvider.resolveCompletion(document, item2!);
 
-        assert.strictEqual(detail, 'Add import from "./Bar.svelte"\n\nclass Bar');
+        assert.strictEqual(
+            detail,
+            `Add import from "./Bar.svelte"${isSvelte5Plus ? '' : '\n\nclass Bar'}`
+        );
     });
 
     it('can auto import new export', async () => {

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

@@ -7,8 +7,11 @@ import { FindComponentReferencesProviderImpl } from '../../../../src/plugins/typ
 import { LSAndTSDocResolver } from '../../../../src/plugins/typescript/LSAndTSDocResolver';
 import { pathToUrl } from '../../../../src/utils';
 import { serviceWarmup } from '../test-utils';
+import { Location } from 'vscode-html-languageservice';
+import { VERSION } from 'svelte/compiler';
 
 const testDir = path.join(__dirname, '..', 'testfiles');
+const isSvelte5Plus = +VERSION.split('.')[0] >= 5;
 
 describe('FindComponentReferencesProvider', function () {
     serviceWarmup(this, testDir);
@@ -54,20 +57,7 @@ describe('FindComponentReferencesProvider', function () {
 
         const results = await provider.findComponentReferences(document.uri.toString());
 
-        assert.deepStrictEqual(results, [
-            {
-                range: {
-                    start: {
-                        line: 8,
-                        character: 15
-                    },
-                    end: {
-                        line: 8,
-                        character: 22
-                    }
-                },
-                uri: getUri('find-component-references-parent.svelte')
-            },
+        const expected: Location[] = [
             {
                 range: {
                     start: {
@@ -120,6 +110,22 @@ describe('FindComponentReferencesProvider', function () {
                 },
                 uri: getUri('find-component-references-parent2.svelte')
             }
-        ]);
+        ];
+        if (!isSvelte5Plus) {
+            expected.unshift({
+                range: {
+                    start: {
+                        line: 8,
+                        character: 15
+                    },
+                    end: {
+                        line: 8,
+                        character: 22
+                    }
+                },
+                uri: getUri('find-component-references-parent.svelte')
+            });
+        }
+        assert.deepStrictEqual(results, expected);
     });
 });