fix(language-core): avoid defineModel breaking ast in lang="js" (#5935)

Author: KazariEX

packages/language-core/lib/codegen/script/scriptSetup.ts

@@ -472,7 +472,9 @@ function* generateModels(
 		yield* codes;
 	}
 	yield `}${endOfLine}`;
-	yield `const ${names.modelEmit} = defineEmits<${names.ModelEmit}>()${endOfLine}`;
+
+	// avoid `defineModel<...>()` to prevent JS AST issues
+	yield `let ${names.modelEmit}!: __VLS_ShortEmits<${names.ModelEmit}>${endOfLine}`;
 }
 
 function* generateModelProp(

packages/language-core/types/template-helpers.d.ts

@@ -93,6 +93,9 @@ declare global {
 			) => any;
 		}
 	>;
+	type __VLS_ShortEmits<E extends Record<string, any[]>> = __VLS_UnionToIntersection<
+		{ [K in keyof E]: (event: K, ...args: E[K]) => void }[keyof E]
+	>;
 	type __VLS_ShortEmitsToObject<E> = E extends Record<string, any[]> ? { [K in keyof E]: (...args: E[K]) => any }
 		: E;
 	type __VLS_ResolveEmits<

packages/tsc/tests/__snapshots__/dts.spec.ts.snap

@@ -186,7 +186,7 @@ exports[`Input: generic/component.vue, Output: generic/component.vue.d.ts 1`] =
             foo: number;
         }) => any;
     };
-    emit: ((e: "bar", data: number) => void) & ((evt: "update:title", value: string) => void);
+    emit: ((e: "bar", data: number) => void) & ((event: "update:title", value: string) => void);
 }>) => import("vue").VNode & {
     __ctx?: Awaited<typeof __VLS_setup>;
 };
@@ -221,7 +221,7 @@ exports[`Input: generic/custom-extension-component.cext, Output: generic/custom-
             foo: number;
         }) => any;
     };
-    emit: ((e: "bar", data: number) => void) & ((evt: "update:title", value: string) => void);
+    emit: ((e: "bar", data: number) => void) & ((event: "update:title", value: string) => void);
 }>) => import("vue").VNode & {
     __ctx?: Awaited<typeof __VLS_setup>;
 };

test-workspace/tsc/#5934/main.vue

@@ -0,0 +1,8 @@
+<script setup>
+// @ts-check
+defineModel('foo');
+</script>
+
+<template>
+	{{ $emit('update:foo', 'bar') }}
+</template>

test-workspace/tsc/#5934/tsconfig.json

@@ -0,0 +1,4 @@
+{
+	"extends": "../../tsconfig.base.json",
+	"include": ["**/*"]
+}

test-workspace/tsc/tsconfig.json

@@ -511,6 +511,9 @@
 		{
 			"path": "./#5899/tsconfig.json"
 		},
+		{
+			"path": "./#5934/tsconfig.json"
+		},
 		{
 			"path": "./#625/tsconfig.json"
 		},