diff --git a/Sources/JavaScriptKit/JSValue.swift b/Sources/JavaScriptKit/JSValue.swift
index fe1400e2..1052aa6b 100644
--- a/Sources/JavaScriptKit/JSValue.swift
+++ b/Sources/JavaScriptKit/JSValue.swift
@@ -109,18 +109,26 @@ public extension JSValue {
     }
 #endif
 
-    /// An unsafe convenience method of `JSObject.subscript(_ index: Int) -> JSValue`
+    /// An unsafe convenience method of `JSObject.subscript(_ index: String) -> JSValue`
     /// - Precondition: `self` must be a JavaScript Object.
     subscript(dynamicMember name: String) -> JSValue {
         get { self.object![name] }
-        set { self.object![name] = newValue }
+        nonmutating set { self.object![name] = newValue }
+    }
+
+    /// An unsafe convenience method of `JSObject.subscript(_ index: String) -> JSValue`
+    /// - Precondition: `self` must be a JavaScript Object.
+    @_disfavoredOverload
+    subscript(dynamicMember name: String) -> ConvertibleToJSValue {
+        get { self.object![name] }
+        nonmutating set { self.object![name] = newValue.jsValue }
     }
 
     /// An unsafe convenience method of `JSObject.subscript(_ index: Int) -> JSValue`
     /// - Precondition: `self` must be a JavaScript Object.
     subscript(_ index: Int) -> JSValue {
         get { object![index] }
-        set { object![index] = newValue }
+        nonmutating set { object![index] = newValue }
     }
 }