Add TypedArrayBuffer.__len__

README.md

@@ -14,7 +14,7 @@ The old emscripten 3.1.73 based branch is available at https://github.com/emscri
 pyjs is  modern [pybind11](https://github.com/pybind/pybind11) + emscripten [Embind](https://emscripten.org/docs/porting/connecting_cpp_and_javascript/embind.html) based
 Python <-> JavaScript foreign function interface (FFI) for wasm/emscripten compiled Python.
 
-The API is loosly based on the  FFI of [pyodide](https://pyodide.org/en/stable/usage/type-conversions.html).
+The API is loosely based on the  FFI of [pyodide](https://pyodide.org/en/stable/usage/type-conversions.html).
 
 ## Full Documentation
 See the [documentation](https://emscripten-forge.github.io/pyjs/) for a full documentation.
@@ -31,7 +31,7 @@ Access Javascript from Python:
 ```python
 import pyjs
 
-# hello world 
+# hello world
 pyjs.js.console.log("Hello, World!")
 
 # create a JavaScript function to add two numbers
@@ -44,7 +44,7 @@ js_function = pyjs.js.Function("a", "b", """
 result = js_function(1, 2)
 ```
 
-Access Python from Javascript:
+Access Python from JavaScript:
 
 ```JavaScript
 // hello world
@@ -53,6 +53,6 @@ pyjs.eval("print('Hello, World!')")
 // eval a python expression and get the result
 const py_list = pyjs.eval("[i for i in range(10)]")
 
-/// access 
+// access
 console.log(py_list.get(0)) // same as py_list[0] on the python side
 ```

src/export_js_proxy.cpp

@@ -298,6 +298,7 @@ namespace pyjs
 
 
         py::class_<TypedArrayBuffer>(m, "TypedArrayBuffer", py::buffer_protocol())
+            .def("__len__", [](const TypedArrayBuffer& self) { return self.m_size; })
             .def_buffer([](TypedArrayBuffer& self) -> py::buffer_info
             {
                 return py::buffer_info(self.m_data, self.m_bytes_per_element, self.m_format_descriptor,

tests/tests/test_pyjs.py

@@ -206,6 +206,18 @@ def test_to_py(test_input, expected_type, expected_value, comperator):
     assert comperator(py_val, expected_value)
 
 
+@pytest.mark.parametrize(
+    "test_input,expected_length",
+    [
+        ("new Uint8Array([1,2,3])", 3),
+        ("new Uint16Array([1,2,3,4])", 4),
+        ("new Float64Array([])", 0),
+    ],
+)
+def test_typed_array_buffer_len(test_input, expected_length):
+    assert len(pyjs.to_py(ensure_js(test_input))) == expected_length
+
+
 @pytest.mark.parametrize(
     "test_input",
     [