pyscript · WebReflection · Aug 6, 2025 · Jul 11, 2025 · Jul 21, 2025 · Aug 6, 2025
diff --git a/core/package-lock.json b/core/package-lock.json
diff --git a/core/package.json b/core/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@pyscript/core",
-    "version": "0.6.65",
+    "version": "0.6.70",
     "type": "module",
     "description": "PyScript",
     "module": "./index.js",
@@ -42,7 +42,7 @@
     },
     "scripts": {
         "server": "echo \"➡️  TESTS @ $(tput bold)http://localhost:8080/tests/$(tput sgr0)\"; npx static-handler --coi .",
-        "build": "export ESLINT_USE_FLAT_CONFIG=true;npm run build:3rd-party && npm run build:stdlib && npm run build:plugins && npm run build:core && npm run build:tests-index && if [ -z \"$NO_MIN\" ]; then eslint src/ && npm run ts && npm run test:integration; fi",
+        "build": "export ESLINT_USE_FLAT_CONFIG=true;npm run build:3rd-party && npm run build:stdlib && npm run build:plugins && npm run build:core && npm run build:tests-index && if [ -z \"$NO_MIN\" ]; then eslint src/ && npm run test:integration; fi",
         "build:core": "rm -rf dist && rollup --config rollup/core.config.js && cp src/3rd-party/*.css dist/",
         "build:flatted": "node rollup/flatted.cjs",
         "build:plugins": "node rollup/plugins.cjs",
@@ -70,7 +70,7 @@
         "@webreflection/utils": "^0.1.1",
         "add-promise-listener": "^0.1.3",
         "basic-devtools": "^0.1.6",
-        "polyscript": "^0.18.3",
+        "polyscript": "^0.18.9",
         "sticky-module": "^0.1.1",
         "to-json-callback": "^0.1.1",
         "type-checked-collections": "^0.1.7"
@@ -80,27 +80,27 @@
         "@codemirror/lang-python": "^6.2.1",
         "@codemirror/language": "^6.11.2",
         "@codemirror/state": "^6.5.2",
-        "@codemirror/view": "^6.38.0",
-        "@playwright/test": "^1.54.0",
+        "@codemirror/view": "^6.38.1",
+        "@playwright/test": "^1.54.2",
         "@rollup/plugin-commonjs": "^28.0.6",
         "@rollup/plugin-node-resolve": "^16.0.1",
         "@rollup/plugin-terser": "^0.4.4",
         "@webreflection/toml-j0.4": "^1.1.4",
         "@xterm/addon-fit": "^0.10.0",
         "@xterm/addon-web-links": "^0.11.0",
         "@xterm/xterm": "^5.5.0",
-        "bun": "^1.2.18",
+        "bun": "^1.2.19",
         "chokidar": "^4.0.3",
         "codedent": "^0.1.2",
         "codemirror": "^6.0.2",
-        "eslint": "^9.30.1",
+        "eslint": "^9.32.0",
         "flatted": "^3.3.3",
-        "rollup": "^4.44.2",
+        "rollup": "^4.46.2",
         "rollup-plugin-postcss": "^4.0.2",
         "rollup-plugin-string": "^3.0.0",
         "static-handler": "^0.5.3",
         "string-width": "^7.2.0",
-        "typescript": "^5.8.3",
+        "typescript": "^5.9.2",
         "xterm-readline": "^1.1.2"
     },
     "repository": {

diff --git a/core/src/stdlib/pyscript.js b/core/src/stdlib/pyscript.js
diff --git a/core/src/stdlib/pyscript/display.py b/core/src/stdlib/pyscript/display.py
@@ -4,6 +4,7 @@
 import re
 
 from pyscript.magic_js import current_target, document, window
+from pyscript.ffi import is_none
 
 _MIME_METHODS = {
     "savefig": "image/png",
@@ -105,13 +106,13 @@ def _format_mime(obj):
         else:
             output = _eval_formatter(obj, method)
 
-        if output is None:
+        if is_none(output):
             continue
         if mime_type not in _MIME_RENDERERS:
             not_available.append(mime_type)
             continue
         break
-    if output is None:
+    if is_none(output):
         if not_available:
             window.console.warn(
                 f"Rendered object requested unavailable MIME renderers: {not_available}"
@@ -135,7 +136,7 @@ def _write(element, value, append=False):
         element.append(out_element)
     else:
         out_element = element.lastElementChild
-        if out_element is None:
+        if is_none(out_element):
             out_element = element
 
     if mime_type in ("application/javascript", "text/html"):
@@ -146,7 +147,7 @@ def _write(element, value, append=False):
 
 
 def display(*values, target=None, append=True):
-    if target is None:
+    if is_none(target):
         target = current_target()
     elif not isinstance(target, str):
         msg = f"target must be str or None, not {target.__class__.__name__}"
@@ -162,7 +163,7 @@ def display(*values, target=None, append=True):
     element = document.getElementById(target)
 
     # If target cannot be found on the page, a ValueError is raised
-    if element is None:
+    if is_none(element):
         msg = f"Invalid selector with id={target}. Cannot be found in the page."
         raise ValueError(msg)
 

diff --git a/core/src/stdlib/pyscript/ffi.py b/core/src/stdlib/pyscript/ffi.py
@@ -2,8 +2,10 @@
     import js
     from pyodide.ffi import create_proxy as _cp
     from pyodide.ffi import to_js as _py_tjs
+    from pyodide.ffi import jsnull
 
     from_entries = js.Object.fromEntries
+    is_none = lambda value: value is None or value is jsnull
 
     def _tjs(value, **kw):
         if not hasattr(kw, "dict_converter"):
@@ -13,6 +15,10 @@ def _tjs(value, **kw):
 except:
     from jsffi import create_proxy as _cp
     from jsffi import to_js as _tjs
+    import js
+
+    jsnull = js.Object.getPrototypeOf(js.Object.prototype)
+    is_none = lambda value: value is None or value is jsnull
 
 create_proxy = _cp
 to_js = _tjs

diff --git a/core/src/stdlib/pyscript/storage.py b/core/src/stdlib/pyscript/storage.py
@@ -1,11 +1,12 @@
 from polyscript import storage as _storage
 from pyscript.flatted import parse as _parse
 from pyscript.flatted import stringify as _stringify
+from pyscript.ffi import is_none
 
 
 # convert a Python value into an IndexedDB compatible entry
 def _to_idb(value):
-    if value is None:
+    if is_none(value):
         return _stringify(["null", 0])
     if isinstance(value, (bool, float, int, str, list, dict, tuple)):
         return _stringify(["generic", value])

diff --git a/core/src/stdlib/pyscript/web.py b/core/src/stdlib/pyscript/web.py
@@ -6,7 +6,7 @@
 # from __future__ import annotations  # CAUTION: This is not supported in MicroPython.
 
 from pyscript import document, when, Event  # noqa: F401
-from pyscript.ffi import create_proxy
+from pyscript.ffi import create_proxy, is_none
 
 
 def wrap_dom_element(dom_element):
@@ -68,8 +68,10 @@ def __init__(self, dom_element=None, classes=None, style=None, **kwargs):
         If `dom_element` is None we are being called to *create* a new element.
         Otherwise, we are being called to *wrap* an existing DOM element.
         """
-        self._dom_element = dom_element or document.createElement(
-            type(self).get_tag_name()
+        self._dom_element = (
+            document.createElement(type(self).get_tag_name())
+            if is_none(dom_element)
+            else dom_element
         )
 
         # HTML on_events attached to the element become pyscript.Event instances.
@@ -195,7 +197,7 @@ def classes(self):
     @property
     def parent(self):
         """Return the element's `parent `Element`."""
-        if self._dom_element.parentElement is None:
+        if is_none(self._dom_element.parentElement):
             return None
 
         return Element.wrap_dom_element(self._dom_element.parentElement)
@@ -1134,7 +1136,7 @@ def snap(
         width = width if width is not None else self.videoWidth
         height = height if height is not None else self.videoHeight
 
-        if to is None:
+        if is_none(to):
             to = canvas(width=width, height=height)
 
         elif isinstance(to, Element):

diff --git a/core/types/core.d.ts b/core/types/core.d.ts
@@ -63,5 +63,5 @@ declare const exportedHooks: {
     };
 };
 declare const exportedConfig: {};
-declare const exportedWhenDefined: any;
+declare const exportedWhenDefined: (type: string) => Promise<object>;
 export { codemirror, stdlib, optional, inputFailure, TYPES, relative_url, exportedPyWorker as PyWorker, exportedMPWorker as MPWorker, exportedHooks as hooks, exportedConfig as config, exportedWhenDefined as whenDefined };