pyscript · WebReflection · Feb 20, 2025 · Feb 17, 2025 · Feb 17, 2025 · Feb 18, 2025
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
@@ -38,6 +38,11 @@ repos:
             additional_dependencies:
                 - tomli
 
+    - repo: https://github.com/astral-sh/ruff-pre-commit
+      rev: v0.9.6
+      hooks:
+          - id: ruff
+
     - repo: https://github.com/hoodmane/pyscript-prettier-precommit
       rev: "v3.0.0-alpha.6"
       hooks:

diff --git a/core/src/stdlib/pyscript/display.py b/core/src/stdlib/pyscript/display.py
@@ -73,14 +73,14 @@ def _eval_formatter(obj, print_method):
     """
     if print_method == "__repr__":
         return repr(obj)
-    elif hasattr(obj, print_method):
+    if hasattr(obj, print_method):
         if print_method == "savefig":
             buf = io.BytesIO()
             obj.savefig(buf, format="png")
             buf.seek(0)
             return base64.b64encode(buf.read()).decode("utf-8")
         return getattr(obj, print_method)()
-    elif print_method == "_repr_mimebundle_":
+    if print_method == "_repr_mimebundle_":
         return {}, {}
     return None
 
@@ -107,7 +107,7 @@ def _format_mime(obj):
 
         if output is None:
             continue
-        elif mime_type not in _MIME_RENDERERS:
+        if mime_type not in _MIME_RENDERERS:
             not_available.append(mime_type)
             continue
         break
@@ -149,9 +149,11 @@ def display(*values, target=None, append=True):
     if target is None:
         target = current_target()
     elif not isinstance(target, str):
-        raise TypeError(f"target must be str or None, not {target.__class__.__name__}")
+        msg = f"target must be str or None, not {target.__class__.__name__}"
+        raise TypeError(msg)
     elif target == "":
-        raise ValueError("Cannot have an empty target")
+        msg = "Cannot have an empty target"
+        raise ValueError(msg)
     elif target.startswith("#"):
         # note: here target is str and not None!
         # align with @when behavior
@@ -161,9 +163,8 @@ def display(*values, target=None, append=True):
 
     # If target cannot be found on the page, a ValueError is raised
     if element is None:
-        raise ValueError(
-            f"Invalid selector with id={target}. Cannot be found in the page."
-        )
+        msg = f"Invalid selector with id={target}. Cannot be found in the page."
+        raise ValueError(msg)
 
     # if element is a <script type="py">, it has a 'target' attribute which
     # points to the visual element holding the displayed values. In that case,

diff --git a/core/src/stdlib/pyscript/events.py b/core/src/stdlib/pyscript/events.py
@@ -36,7 +36,8 @@ def add_listener(self, listener):
             if listener not in self._listeners:
                 self._listeners.append(listener)
         else:
-            raise ValueError("Listener must be callable or awaitable.")
+            msg = "Listener must be callable or awaitable."
+            raise ValueError(msg)
 
     def remove_listener(self, *args):
         """
@@ -76,7 +77,8 @@ def when(target, *args, **kwargs):
         # Extract the selector from the arguments or keyword arguments.
         selector = args[0] if args else kwargs.pop("selector")
         if not selector:
-            raise ValueError("No selector provided.")
+            msg = "No selector provided."
+            raise ValueError(msg)
         # Grab the DOM elements to which the target event will be attached.
         from pyscript.web import Element, ElementCollection
 

diff --git a/core/src/stdlib/pyscript/flatted.py b/core/src/stdlib/pyscript/flatted.py
@@ -31,7 +31,7 @@ def _object_keys(value):
 
 
 def _is_array(value):
-    return isinstance(value, list) or isinstance(value, tuple)
+    return isinstance(value, (list, tuple))
 
 
 def _is_object(value):
@@ -60,10 +60,10 @@ def _loop(keys, input, known, output):
 
 
 def _ref(key, value, input, known, output):
-    if _is_array(value) and not value in known:
+    if _is_array(value) and value not in known:
         known.append(value)
         value = _loop(_array_keys(value), input, known, value)
-    elif _is_object(value) and not value in known:
+    elif _is_object(value) and value not in known:
         known.append(value)
         value = _loop(_object_keys(value), input, known, value)
 

diff --git a/core/src/stdlib/pyscript/magic_js.py b/core/src/stdlib/pyscript/magic_js.py
@@ -25,6 +25,7 @@ def __getattr__(self, field):
         # avoid pyodide looking for non existent fields
         if not field.startswith("_"):
             return getattr(getattr(js_modules, self.name), field)
+        return None
 
 
 # generate N modules in the system that will proxy the real value

diff --git a/core/src/stdlib/pyscript/media.py b/core/src/stdlib/pyscript/media.py
@@ -44,8 +44,7 @@ async def load(cls, audio=False, video=True):
             for k in video:
                 setattr(options.video, k, to_js(video[k]))
 
-        stream = await window.navigator.mediaDevices.getUserMedia(options)
-        return stream
+        return await window.navigator.mediaDevices.getUserMedia(options)
 
     async def get_stream(self):
         key = self.kind.replace("input", "").replace("output", "")

diff --git a/core/src/stdlib/pyscript/storage.py b/core/src/stdlib/pyscript/storage.py
@@ -10,10 +10,11 @@ def _to_idb(value):
     if isinstance(value, (bool, float, int, str, list, dict, tuple)):
         return _stringify(["generic", value])
     if isinstance(value, bytearray):
-        return _stringify(["bytearray", [v for v in value]])
+        return _stringify(["bytearray", list(value)])
     if isinstance(value, memoryview):
-        return _stringify(["memoryview", [v for v in value]])
-    raise TypeError(f"Unexpected value: {value}")
+        return _stringify(["memoryview", list(value)])
+    msg = f"Unexpected value: {value}"
+    raise TypeError(msg)
 
 
 # convert an IndexedDB compatible entry into a Python value
@@ -56,5 +57,6 @@ async def sync(self):
 
 async def storage(name="", storage_class=Storage):
     if not name:
-        raise ValueError("The storage name must be defined")
+        msg = "The storage name must be defined"
+        raise ValueError(msg)
     return storage_class(await _storage(f"@pyscript/{name}"))
diff --git a/core/src/stdlib/pyscript/util.py b/core/src/stdlib/pyscript/util.py
@@ -11,7 +11,7 @@ def as_bytearray(buffer):
     ui8a = js.Uint8Array.new(buffer)
     size = ui8a.length
     ba = bytearray(size)
-    for i in range(0, size):
+    for i in range(size):
         ba[i] = ui8a[i]
     return ba
 

diff --git a/core/src/stdlib/pyscript/web.py b/core/src/stdlib/pyscript/web.py
@@ -2,7 +2,10 @@
 
 # `when` is not used in this module. It is imported here save the user an additional
 # import (i.e. they can get what they need from `pyscript.web`).
-from pyscript import document, when, Event  # NOQA
+
+# 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
 
 
@@ -100,7 +103,7 @@ def __getitem__(self, key):
         If `key` is an integer or a slice we use it to index/slice the element's
         children. Otherwise, we use `key` as a query selector.
         """
-        if isinstance(key, int) or isinstance(key, slice):
+        if isinstance(key, (int, slice)):
             return self.children[key]
 
         return self.find(key)
@@ -120,7 +123,7 @@ def __getattr__(self, name):
         # attribute `for` which is a Python keyword, so you can access it on the
         # Element instance via `for_`).
         if name.endswith("_"):
-            name = name[:-1]
+            name = name[:-1]  # noqa: FURB188 No str.removesuffix() in MicroPython.
         return getattr(self._dom_element, name)
 
     def __setattr__(self, name, value):
@@ -138,7 +141,7 @@ def __setattr__(self, name, value):
             # attribute `for` which is a Python keyword, so you can access it on the
             # Element instance via `for_`).
             if name.endswith("_"):
-                name = name[:-1]
+                name = name[:-1]  # noqa: FURB188 No str.removesuffix() in MicroPython.
 
             if name.startswith("on_"):
                 # Ensure on-events are cached in the _on_events dict if the
@@ -152,10 +155,12 @@ def get_event(self, name):
         Get an `Event` instance for the specified event name.
         """
         if not name.startswith("on_"):
-            raise ValueError("Event names must start with 'on_'.")
+            msg = "Event names must start with 'on_'."
+            raise ValueError(msg)
         event_name = name[3:]  # Remove the "on_" prefix.
         if not hasattr(self._dom_element, event_name):
-            raise ValueError(f"Element has no '{event_name}' event.")
+            msg = f"Element has no '{event_name}' event."
+            raise ValueError(msg)
         if name in self._on_events:
             return self._on_events[name]
         # Such an on-event exists in the DOM element, but we haven't yet
@@ -203,7 +208,7 @@ def append(self, *items):
             # We check for list/tuple here and NOT for any iterable as it will match
             # a JS Nodelist which is handled explicitly below.
             # NodeList.
-            elif isinstance(item, list) or isinstance(item, tuple):
+            elif isinstance(item, (list, tuple)):
                 for child in item:
                     self.append(child)
 
@@ -227,10 +232,11 @@ def append(self, *items):
 
                     except AttributeError:
                         # Nope! This is not an element or a NodeList.
-                        raise TypeError(
+                        msg = (
                             f'Element "{item}" is a proxy object, "'
                             f"but not a valid element or a NodeList."
                         )
+                        raise TypeError(msg)
 
     def clone(self, clone_id=None):
         """Make a clone of the element (clones the underlying DOM object too)."""
@@ -401,9 +407,8 @@ def add(self, value=None, html=None, text=None, before=None, **kwargs):
 
         new_option = option(**kwargs)
 
-        if before:
-            if isinstance(before, Element):
-                before = before._dom_element
+        if before and isinstance(before, Element):
+            before = before._dom_element
 
         self._element._dom_element.add(new_option._dom_element, before)
 
@@ -463,7 +468,7 @@ def __init__(
         )
 
         for child in list(args) + (children or []):
-            if isinstance(child, Element) or isinstance(child, ElementCollection):
+            if isinstance(child, (Element, ElementCollection)):
                 self.append(child)
 
             else:
@@ -493,14 +498,13 @@ def __eq__(self, other):
         )
 
     def __iter__(self):
-        for class_name in self._all_class_names():
-            yield class_name
+        yield from self._all_class_names()
 
     def __len__(self):
         return len(self._all_class_names())
 
     def __repr__(self):
-        return f"ClassesCollection({repr(self._collection)})"
+        return f"ClassesCollection({self._collection!r})"
 
     def __str__(self):
         return " ".join(self._all_class_names())
@@ -553,7 +557,7 @@ def __setitem__(self, key, value):
             element.style[key] = value
 
     def __repr__(self):
-        return f"StyleCollection({repr(self._collection)})"
+        return f"StyleCollection({self._collection!r})"
 
     def remove(self, key):
         """Remove a CSS property from the elements in the collection."""
@@ -588,7 +592,7 @@ def __getitem__(self, key):
         if isinstance(key, int):
             return self._elements[key]
 
-        elif isinstance(key, slice):
+        if isinstance(key, slice):
             return ElementCollection(self._elements[key])
 
         return self.find(key)
@@ -1125,7 +1129,8 @@ def snap(
 
         elif isinstance(to, Element):
             if to.tag != "canvas":
-                raise TypeError("Element to snap to must be a canvas.")
+                msg = "Element to snap to must be a canvas."
+                raise TypeError(msg)
 
         elif getattr(to, "tagName", "") == "CANVAS":
             to = canvas(dom_element=to)
@@ -1134,10 +1139,12 @@ def snap(
         elif isinstance(to, str):
             nodelist = document.querySelectorAll(to)  # NOQA
             if nodelist.length == 0:
-                raise TypeError("No element with selector {to} to snap to.")
+                msg = "No element with selector {to} to snap to."
+                raise TypeError(msg)
 
             if nodelist[0].tagName != "CANVAS":
-                raise TypeError("Element to snap to must be a canvas.")
+                msg = "Element to snap to must be a canvas."
+                raise TypeError(msg)
 
             to = canvas(dom_element=nodelist[0])
 

diff --git a/core/src/stdlib/pyscript/websocket.py b/core/src/stdlib/pyscript/websocket.py
@@ -24,7 +24,7 @@ def __getattr__(self, attr):
         return value
 
 
-class WebSocket(object):
+class WebSocket:
     CONNECTING = 0
     OPEN = 1
     CLOSING = 2

diff --git a/core/src/stdlib/pyscript/workers.py b/core/src/stdlib/pyscript/workers.py
@@ -25,10 +25,12 @@ async def create_named_worker(src="", name="", config=None, type="py"):
     from json import dumps
 
     if not src:
-        raise ValueError("Named workers require src")
+        msg = "Named workers require src"
+        raise ValueError(msg)
 
     if not name:
-        raise ValueError("Named workers require a name")
+        msg = "Named workers require a name"
+        raise ValueError(msg)
 
     s = _js.document.createElement("script")
     s.type = type
@@ -37,7 +39,7 @@ async def create_named_worker(src="", name="", config=None, type="py"):
     _set(s, "name", name)
 
     if config:
-        _set(s, "config", isinstance(config, str) and config or dumps(config))
+        _set(s, "config", (isinstance(config, str) and config) or dumps(config))
 
     _js.document.body.append(s)
     return await workers[name]
diff --git a/core/tests/javascript/pyodide-cache/index.py b/core/tests/javascript/pyodide-cache/index.py
@@ -1,6 +1,6 @@
-import numpy
-import matplotlib
+import numpy as np
+import matplotlib as mpl
 
 # just do something with the packages
-print(len(dir(numpy)))
-print(len(dir(matplotlib)))
+print(len(dir(np)))
+print(len(dir(mpl)))
diff --git a/core/tests/javascript/workers/worker.py b/core/tests/javascript/workers/worker.py
@@ -4,4 +4,4 @@ def runtime_version():
     return sys.version
 
 
-__export__ = ['runtime_version']
+__export__ = ["runtime_version"]
diff --git a/core/tests/manual/fs/index.py b/core/tests/manual/fs/index.py
@@ -8,7 +8,7 @@
     await fs.mount("/persistent")
 
     print(
-        RUNNING_IN_WORKER and "Worker" or "Main",
+        (RUNNING_IN_WORKER and "Worker") or "Main",
         os.listdir("/persistent"),
     )
Original file line number	Diff line number	Diff line change
Expand Up		@@ -4,4 +4,4 @@ def runtime_version():
		return sys.version


		__export__ = ['runtime_version']
		__export__ = ["runtime_version"]