diff --git a/frontend/common/parse_launch_params.js b/frontend/common/parse_launch_params.js
new file mode 100644
index 0000000000..fe801ec0d9
--- /dev/null
+++ b/frontend/common/parse_launch_params.js
@@ -0,0 +1,38 @@
+/**
+ *
+ * @return {import("../components/Editor.js").LaunchParameters}
+ */
+export const parse_launch_params = () => {
+    const url_params = new URLSearchParams(window.location.search)
+
+    return {
+        //@ts-ignore
+        notebook_id: url_params.get("id") ?? window.pluto_notebook_id,
+        //@ts-ignore
+        statefile: url_params.get("statefile") ?? window.pluto_statefile,
+        //@ts-ignore
+        statefile_integrity: url_params.get("statefile_integrity") ?? window.pluto_statefile_integrity,
+        //@ts-ignore
+        notebookfile: url_params.get("notebookfile") ?? window.pluto_notebookfile,
+        //@ts-ignore
+        notebookfile_integrity: url_params.get("notebookfile_integrity") ?? window.pluto_notebookfile_integrity,
+        //@ts-ignore
+        disable_ui: !!(url_params.get("disable_ui") ?? window.pluto_disable_ui),
+        //@ts-ignore
+        preamble_html: url_params.get("preamble_html") ?? window.pluto_preamble_html,
+        //@ts-ignore
+        isolated_cell_ids: url_params.has("isolated_cell_id") ? url_params.getAll("isolated_cell_id") : window.pluto_isolated_cell_ids,
+        //@ts-ignore
+        binder_url: url_params.get("binder_url") ?? window.pluto_binder_url,
+        //@ts-ignore
+        pluto_server_url: url_params.get("pluto_server_url") ?? window.pluto_pluto_server_url,
+        //@ts-ignore
+        slider_server_url: url_params.get("slider_server_url") ?? window.pluto_slider_server_url,
+        //@ts-ignore
+        recording_url: url_params.get("recording_url") ?? window.pluto_recording_url,
+        //@ts-ignore
+        recording_url_integrity: url_params.get("recording_url_integrity") ?? window.pluto_recording_url_integrity,
+        //@ts-ignore
+        recording_audio_url: url_params.get("recording_audio_url") ?? window.pluto_recording_audio_url,
+    }
+}
diff --git a/frontend/editor.js b/frontend/editor.js
index 42a73b6300..bdddaf85ca 100644
--- a/frontend/editor.js
+++ b/frontend/editor.js
@@ -6,6 +6,7 @@ import { FetchProgress, read_Uint8Array_with_progress } from "./components/Fetch
 import { unpack } from "./common/MsgPack.js"
 import { RawHTMLContainer } from "./components/CellOutput.js"
 import { ProcessStatus } from "./common/ProcessStatus.js"
+import { parse_launch_params } from "./common/parse_launch_params.js"
 
 const url_params = new URLSearchParams(window.location.search)
 
@@ -25,40 +26,7 @@ export const set_disable_ui_css = (val) => {
 /////////////
 // the rest:
 
-/**
- *
- * @type {import("./components/Editor.js").LaunchParameters}
- */
-const launch_params = {
-    //@ts-ignore
-    notebook_id: url_params.get("id") ?? window.pluto_notebook_id,
-    //@ts-ignore
-    statefile: url_params.get("statefile") ?? window.pluto_statefile,
-    //@ts-ignore
-    statefile_integrity: url_params.get("statefile_integrity") ?? window.pluto_statefile_integrity,
-    //@ts-ignore
-    notebookfile: url_params.get("notebookfile") ?? window.pluto_notebookfile,
-    //@ts-ignore
-    notebookfile_integrity: url_params.get("notebookfile_integrity") ?? window.pluto_notebookfile_integrity,
-    //@ts-ignore
-    disable_ui: !!(url_params.get("disable_ui") ?? window.pluto_disable_ui),
-    //@ts-ignore
-    preamble_html: url_params.get("preamble_html") ?? window.pluto_preamble_html,
-    //@ts-ignore
-    isolated_cell_ids: url_params.has("isolated_cell_id") ? url_params.getAll("isolated_cell_id") : window.pluto_isolated_cell_ids,
-    //@ts-ignore
-    binder_url: url_params.get("binder_url") ?? window.pluto_binder_url,
-    //@ts-ignore
-    pluto_server_url: url_params.get("pluto_server_url") ?? window.pluto_pluto_server_url,
-    //@ts-ignore
-    slider_server_url: url_params.get("slider_server_url") ?? window.pluto_slider_server_url,
-    //@ts-ignore
-    recording_url: url_params.get("recording_url") ?? window.pluto_recording_url,
-    //@ts-ignore
-    recording_url_integrity: url_params.get("recording_url_integrity") ?? window.pluto_recording_url_integrity,
-    //@ts-ignore
-    recording_audio_url: url_params.get("recording_audio_url") ?? window.pluto_recording_audio_url,
-}
+const launch_params = parse_launch_params()
 
 const truthy = (x) => x === "" || x === "true"
 const falsey = (x) => x === "false"