diff --git a/fastn-resolved/src/web_component.rs b/fastn-resolved/src/web_component.rs
index c5d5add2b..8d4fe2d8f 100644
--- a/fastn-resolved/src/web_component.rs
+++ b/fastn-resolved/src/web_component.rs
@@ -20,4 +20,14 @@ impl WebComponentDefinition {
             line_number,
         }
     }
+
+    pub fn js(&self) -> Option<&str> {
+        match self.js {
+            fastn_resolved::PropertyValue::Value { ref value, .. } => match value {
+                fastn_resolved::Value::String { text } => Some(text),
+                _ => None,
+            },
+            _ => None,
+        }
+    }
 }
diff --git a/v0.5/fastn-compiler/src/utils.rs b/v0.5/fastn-compiler/src/utils.rs
index 5bdeca505..c9cff1921 100644
--- a/v0.5/fastn-compiler/src/utils.rs
+++ b/v0.5/fastn-compiler/src/utils.rs
@@ -24,10 +24,17 @@ impl fastn_compiler::Compiler {
 
     pub(crate) fn external_js_files(
         &self,
-        _needed_symbols: &indexmap::IndexMap<String, &fastn_resolved::Definition>,
+        used_definitions: &indexmap::IndexMap<String, &fastn_resolved::Definition>,
     ) -> Vec<String> {
-        // go through needed_symbols and get the external js files
-        todo!()
+        used_definitions
+            .values()
+            .filter_map(|definition| match definition {
+                fastn_resolved::Definition::WebComponent(web_component) => {
+                    web_component.js().map(ToOwned::to_owned)
+                }
+                _ => None,
+            })
+            .collect()
     }
 
     pub(crate) fn external_css_files(