feat: support generics attribute for JSDoc (#2624)

#2618

Author: dummdidumm

Diff for: packages/svelte2tsx/src/svelte2tsx/addComponentExport.ts

@@ -49,6 +49,7 @@ function addGenericsComponentExport({
     fileName,
     mode,
     usesAccessors,
+    isTsFile,
     str,
     generics,
     usesSlots,
@@ -65,6 +66,8 @@ function addGenericsComponentExport({
         return `ReturnType<__sveltets_Render${genericsRef}['${forPart}']>`;
     }
 
+    // TODO once Svelte 4 compatibility is dropped, we can simplify this, because since TS 4.7 it is possible to use generics
+    // like this: `typeof render<T>` - which wasn't possibly before, hence the class + methods workaround.
     let statement = `
 class __sveltets_Render${genericsDef} {
     props() {
@@ -76,14 +79,23 @@ class __sveltets_Render${genericsDef} {
     slots() {
         return render${genericsRef}().slots;
     }
-${
-    isSvelte5
+`;
+
+    // For Svelte 5+ we assume TS > 4.7
+    if (isSvelte5 && !isTsFile && exportedNames.usesRunes()) {
+        statement = `
+class __sveltets_Render${genericsDef} {
+    props(): ReturnType<typeof render${genericsRef}>['props'] { return null as any; }
+    events(): ReturnType<typeof render${genericsRef}>['events'] { return null as any; }
+    slots(): ReturnType<typeof render${genericsRef}>['slots'] { return null as any; }
+`;
+    }
+
+    statement += isSvelte5
         ? `    bindings() { return ${exportedNames.createBindingsStr()}; }
     exports() { return ${exportedNames.hasExports() ? `render${genericsRef}().exports` : '{}'}; }
-}`
-        : '}'
-}
-`;
+}\n`
+        : '}\n';
 
     const svelteComponentClass = noSvelteComponentTyped
         ? 'SvelteComponent'

Diff for: packages/svelte2tsx/src/svelte2tsx/createRenderFunction.ts

@@ -2,7 +2,11 @@ import MagicString from 'magic-string';
 import { Node } from 'estree-walker';
 import { ComponentEvents } from './nodes/ComponentEvents';
 import { InstanceScriptProcessResult } from './processInstanceScriptContent';
-import { surroundWithIgnoreComments } from '../utils/ignore';
+import {
+    IGNORE_END_COMMENT,
+    IGNORE_START_COMMENT,
+    surroundWithIgnoreComments
+} from '../utils/ignore';
 
 export interface CreateRenderFunctionPara extends InstanceScriptProcessResult {
     str: MagicString;
@@ -12,6 +16,7 @@ export interface CreateRenderFunctionPara extends InstanceScriptProcessResult {
     events: ComponentEvents;
     uses$$SlotsInterface: boolean;
     svelte5Plus: boolean;
+    isTsFile: boolean;
     mode?: 'ts' | 'dts';
 }
 
@@ -27,6 +32,7 @@ export function createRenderFunction({
     uses$$slots,
     uses$$SlotsInterface,
     generics,
+    isTsFile,
     mode
 }: CreateRenderFunctionPara) {
     const htmlx = str.original;
@@ -70,8 +76,12 @@ export function createRenderFunction({
                 end--;
             }
             str.overwrite(scriptTag.start + 1, start - 1, `function render`);
-            str.overwrite(start - 1, start, `<`); // if the generics are unused, only this char is colored opaque
-            str.overwrite(end, scriptTagEnd, `>() {${propsDecl}\n`);
+            str.overwrite(start - 1, start, isTsFile ? '<' : `<${IGNORE_START_COMMENT}`); // if the generics are unused, only this char is colored opaque
+            str.overwrite(
+                end,
+                scriptTagEnd,
+                `>${isTsFile ? '' : IGNORE_END_COMMENT}() {${propsDecl}\n`
+            );
         } else {
             str.overwrite(
                 scriptTag.start + 1,

Diff for: packages/svelte2tsx/src/svelte2tsx/index.ts

@@ -48,6 +48,7 @@ export function svelte2tsx(
     const str = new MagicString(svelte);
     const basename = path.basename(options.filename || '');
     const svelte5Plus = Number(options.version![0]) > 4;
+    const isTsFile = options?.isTsFile;
 
     // process the htmlx as a svelte template
     let {
@@ -95,14 +96,7 @@ export function svelte2tsx(
         : instanceScriptTarget;
     const implicitStoreValues = new ImplicitStoreValues(resolvedStores, renderFunctionStart);
     //move the instance script and process the content
-    let exportedNames = new ExportedNames(
-        str,
-        0,
-        basename,
-        options?.isTsFile,
-        svelte5Plus,
-        isRunes
-    );
+    let exportedNames = new ExportedNames(str, 0, basename, isTsFile, svelte5Plus, isRunes);
     let generics = new Generics(str, 0, { attributes: [] } as any);
     let uses$$SlotsInterface = false;
     if (scriptTag) {
@@ -117,7 +111,7 @@ export function svelte2tsx(
             implicitStoreValues,
             options.mode,
             moduleAst,
-            options?.isTsFile,
+            isTsFile,
             basename,
             svelte5Plus,
             isRunes
@@ -148,6 +142,7 @@ export function svelte2tsx(
         uses$$SlotsInterface,
         generics,
         svelte5Plus,
+        isTsFile,
         mode: options.mode
     });
 
@@ -195,7 +190,7 @@ export function svelte2tsx(
         str,
         canHaveAnyProp: !exportedNames.uses$$Props && (uses$$props || uses$$restProps),
         events,
-        isTsFile: options?.isTsFile,
+        isTsFile,
         exportedNames,
         usesAccessors,
         usesSlots: slots.size > 0,

Diff for: packages/svelte2tsx/test/svelte2tsx/samples/generics-attribute.v5/expectedv2.ts

@@ -0,0 +1,28 @@
+///<reference types="svelte" />
+;function render</*Ωignore_startΩ*/A, B extends keyof A, C extends boolean>/*Ωignore_endΩ*/() {
+
+    /** @typedef {{ a: A; b: B; c: C }}  $$ComponentProps *//** @type {$$ComponentProps} */
+    const { a, b, c } = $props();
+
+     function getA() {
+        return a;
+    }
+;
+async () => {};
+return { props: /** @type {$$ComponentProps} */({}), exports: /** @type {{getA: typeof getA}} */ ({}), bindings: __sveltets_$$bindings(''), slots: {}, events: {} }}
+class __sveltets_Render<A,B extends keyof A,C extends boolean> {
+    props(): ReturnType<typeof render<A,B,C>>['props'] { return null as any; }
+    events(): ReturnType<typeof render<A,B,C>>['events'] { return null as any; }
+    slots(): ReturnType<typeof render<A,B,C>>['slots'] { return null as any; }
+    bindings() { return __sveltets_$$bindings(''); }
+    exports() { return render<A,B,C>().exports; }
+}
+
+interface $$IsomorphicComponent {
+    new <A,B extends keyof A,C extends boolean>(options: import('svelte').ComponentConstructorOptions<ReturnType<__sveltets_Render<A,B,C>['props']>>): import('svelte').SvelteComponent<ReturnType<__sveltets_Render<A,B,C>['props']>, ReturnType<__sveltets_Render<A,B,C>['events']>, ReturnType<__sveltets_Render<A,B,C>['slots']>> & { $$bindings?: ReturnType<__sveltets_Render<A,B,C>['bindings']> } & ReturnType<__sveltets_Render<A,B,C>['exports']>;
+    <A,B extends keyof A,C extends boolean>(internal: unknown, props: ReturnType<__sveltets_Render<A,B,C>['props']> & {}): ReturnType<__sveltets_Render<A,B,C>['exports']>;
+    z_$$bindings?: ReturnType<__sveltets_Render<any,any,any>['bindings']>;
+}
+const Input__SvelteComponent_: $$IsomorphicComponent = null as any;
+/*Ωignore_startΩ*/type Input__SvelteComponent_<A,B extends keyof A,C extends boolean> = InstanceType<typeof Input__SvelteComponent_<A,B,C>>;
+/*Ωignore_endΩ*/export default Input__SvelteComponent_;

Diff for: packages/svelte2tsx/test/svelte2tsx/samples/generics-attribute.v5/input.svelte

@@ -0,0 +1,8 @@
+<script generics="A, B extends keyof A, C extends boolean">
+    /** @type {{ a: A; b: B; c: C }} */
+    const { a, b, c } = $props();
+
+    export function getA() {
+        return a;
+    }
+</script>

Diff for: packages/svelte2tsx/test/svelte2tsx/samples/generic-attribute-const-modifier/expected-svelte5.ts renamed to packages/svelte2tsx/test/svelte2tsx/samples/ts-generic-attribute-const-modifier/expected-svelte5.ts

@@ -4,7 +4,7 @@
  let items: T/*Ωignore_startΩ*/;items = __sveltets_2_any(items);/*Ωignore_endΩ*/;
 ;
 async () => {};
-return { props: {items: items}, exports: {}, bindings: "", slots: {}, events: {} }}
+return { props: {items: items} as {items: T}, exports: {}, bindings: "", slots: {}, events: {} }}
 class __sveltets_Render<const T extends readonly string[]> {
     props() {
         return render<T>().props;

Diff for: packages/svelte2tsx/test/svelte2tsx/samples/generic-attribute-const-modifier/expectedv2.ts renamed to packages/svelte2tsx/test/svelte2tsx/samples/ts-generic-attribute-const-modifier/expectedv2.ts

@@ -4,7 +4,7 @@
  let items: T/*Ωignore_startΩ*/;items = __sveltets_2_any(items);/*Ωignore_endΩ*/;
 ;
 async () => {};
-return { props: {items: items}, slots: {}, events: {} }}
+return { props: {items: items} as {items: T}, slots: {}, events: {} }}
 class __sveltets_Render<const T extends readonly string[]> {
     props() {
         return render<T>().props;