fix: handle object literal in MustacheTag (#2805)

jasonlyu123 · web-flow · commit 23db5a4bc858 · 2025-07-25T08:28:24.000+02:00
diff --git a/packages/svelte2tsx/src/htmlxtojsx_v2/nodes/MustacheTag.ts b/packages/svelte2tsx/src/htmlxtojsx_v2/nodes/MustacheTag.ts
@@ -10,6 +10,13 @@ export function handleMustacheTag(str: MagicString, node: BaseNode, parent: Base
         // handled inside Attribute.ts / StyleDirective.ts
         return;
     }
+    const text = str.original.slice(node.start + 1, node.end - 1);
+    if (text.trimStart().startsWith('{')) {
+        // possibly an object literal, wrapping it in parentheses so it's treated as an expression
+        str.overwrite(node.start, node.start + 1, ';(', { contentOnly: true });
+        str.overwrite(node.end - 1, node.end, ');', { contentOnly: true });
+        return;
+    }
     str.overwrite(node.start, node.start + 1, '', { contentOnly: true });
     str.overwrite(node.end - 1, node.end, ';', { contentOnly: true });
 }
diff --git a/packages/svelte2tsx/test/htmlx2jsx/samples/mustache-tag-object-literal/expectedv2.js b/packages/svelte2tsx/test/htmlx2jsx/samples/mustache-tag-object-literal/expectedv2.js
@@ -0,0 +1,5 @@
+;({ 
+    toString() { return "Hello World" } 
+});
+
+;({ a: '' }['a']);
diff --git a/packages/svelte2tsx/test/htmlx2jsx/samples/mustache-tag-object-literal/input.svelte b/packages/svelte2tsx/test/htmlx2jsx/samples/mustache-tag-object-literal/input.svelte
@@ -0,0 +1,5 @@
+{{ 
+    toString() { return "Hello World" } 
+}}
+
+{{ a: '' }['a']}

Original file line number	Diff line number	Diff line change
`@@ -10,6 +10,13 @@ export function handleMustacheTag(str: MagicString, node: BaseNode, parent: Base`
`10`	`10`	`// handled inside Attribute.ts / StyleDirective.ts`
`11`	`11`	`return;`
`12`	`12`	`}`
	`13`	`+ const text = str.original.slice(node.start + 1, node.end - 1);`
	`14`	`+ if (text.trimStart().startsWith('{')) {`
	`15`	`+ // possibly an object literal, wrapping it in parentheses so it's treated as an expression`
	`16`	`+ str.overwrite(node.start, node.start + 1, ';(', { contentOnly: true });`
	`17`	`+ str.overwrite(node.end - 1, node.end, ');', { contentOnly: true });`
	`18`	`+ return;`
	`19`	`+ }`
`13`	`20`	`str.overwrite(node.start, node.start + 1, '', { contentOnly: true });`
`14`	`21`	`str.overwrite(node.end - 1, node.end, ';', { contentOnly: true });`
`15`	`22`	`}`
-Original file line number
+Diff line change
@@ @@ -0,0 +1,5 @@ @@
 +;({
 +    toString() { return "Hello World" }
 +});
++
 +;({ a: '' }['a']);