Updated Polyscript with its workers feature (#2104)

* Updated Polyscript with its workers feature
* Worked around the inconsistent behavior between Pyodide and MicroPython
* Fixed Pyodide greedy access to undesired Proxy fields

pyscript.core/src/stdlib/pyscript/__init__.py

@@ -46,6 +46,9 @@ from pyscript.magic_js import (
 from pyscript.storage import Storage, storage
 from pyscript.websocket import WebSocket
 
+if not RUNNING_IN_WORKER:
+    from pyscript.workers import create_named_worker, workers
+
 try:
     from pyscript.event_handling import when
 except:

pyscript.core/src/stdlib/pyscript/workers.py

@@ -0,0 +1,43 @@
+import js as _js
+from polyscript import workers as _workers
+
+_get = _js.Reflect.get
+
+
+def _set(script, name, value=""):
+    script.setAttribute(name, value)
+
+
+# this solves an inconsistency between Pyodide and MicroPython
+# @see https://github.com/pyscript/pyscript/issues/2106
+class _ReadOnlyProxy:
+    def __getitem__(self, name):
+        return _get(_workers, name)
+
+    def __getattr__(self, name):
+        return _get(_workers, name)
+
+
+workers = _ReadOnlyProxy()
+
+
+async def create_named_worker(src="", name="", config=None, type="py"):
+    from json import dumps
+
+    if not src:
+        raise ValueError("Named workers require src")
+
+    if not name:
+        raise ValueError("Named workers require a name")
+
+    s = _js.document.createElement("script")
+    s.type = type
+    s.src = src
+    _set(s, "worker")
+    _set(s, "name", name)
+
+    if config:
+        _set(s, "config", isinstance(config, str) and config or dumps(config))
+
+    _js.document.body.append(s)
+    return await workers[name]