Fix #1899 - Expose pyscript.js_modules as module (#1902)

* Fix #1899 - Expose pyscript.js_modules as module

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* Fix #1899 - Make import as smooth as in polyscript

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

pyscript.core/src/stdlib/pyscript/magic_js.py

@@ -1,9 +1,28 @@
+import sys
+
 import js as globalThis
 from polyscript import js_modules
 from pyscript.util import NotSupported
 
 RUNNING_IN_WORKER = not hasattr(globalThis, "document")
 
+
+# allow `from pyscript.js_modules.xxx import yyy`
+class JSModule(object):
+    def __init__(self, name):
+        self.name = name
+
+    def __getattr__(self, field):
+        # avoid pyodide looking for non existent fields
+        if not field.startswith("_"):
+            return getattr(getattr(js_modules, self.name), field)
+
+
+# generate N modules in the system that will proxy the real value
+for name in globalThis.Reflect.ownKeys(js_modules):
+    sys.modules[f"pyscript.js_modules.{name}"] = JSModule(name)
+sys.modules["pyscript.js_modules"] = js_modules
+
 if RUNNING_IN_WORKER:
     import js
     import polyscript