fix(jupyter): more robust Deno.jupyter namespace (#20710)

1 files changed, 7 insertions, 0 deletions

diff --git a/runtime/js/99_main.js b/runtime/js/99_main.js
index 15e4936b1..d2a28838a 100644
--- a/runtime/js/99_main.js
+++ b/runtime/js/99_main.js
@@ -545,12 +545,19 @@ function bootstrapMainRuntime(runtimeOptions) {
     // TODO(bartlomieju): this is not ideal, but because we use `ObjectAssign`
     // above any properties that are defined elsewhere using `Object.defineProperty`
     // are lost.
+    let jupyterNs = undefined;
     ObjectDefineProperty(finalDenoNs, "jupyter", {
       get() {
+        if (jupyterNs) {
+          return jupyterNs;
+        }
         throw new Error(
           "Deno.jupyter is only available in `deno jupyter` subcommand.",
         );
       },
+      set(val) {
+        jupyterNs = val;
+      },
     });
   }