I can bind multi-select

src/myfasthtml/core/bindings.py

@@ -7,7 +7,7 @@ from fasthtml.fastapp import fast_app
 from myutils.observable import make_observable, bind, collect_return_values, unbind
 
 from myfasthtml.core.constants import Routes, ROUTE_ROOT
-from myfasthtml.core.utils import get_default_attr, get_default_ft_attr, is_checkbox, is_radio
+from myfasthtml.core.utils import get_default_attr, get_default_ft_attr, is_checkbox, is_radio, is_select
 
 bindings_app, bindings_rt = fast_app()
 logger = logging.getLogger("Bindings")
@@ -16,11 +16,13 @@ logger = logging.getLogger("Bindings")
 class UpdateMode(Enum):
   ValueChange = "ValueChange"
   AttributePresence = "AttributePresence"
+  SelectValueChange = "SelectValueChange"
 
 
 class DetectionMode(Enum):
   ValueChange = "ValueChange"
   AttributePresence = "AttributePresence"
+  SelectValueChange = "SelectValueChange"
 
 
 class AttrChangedDetection:
@@ -51,6 +53,19 @@ class ValueChangedDetection(AttrChangedDetection):
     return False, None
 
 
+class SelectValueChangedDetection(AttrChangedDetection):
+  """
+  Search for the attribute that is modified.
+  """
+  
+  def matches(self, values):
+    for key, value in values.items():
+      if key == self.attr:
+        return True, value
+    
+    return True, []
+
+
 class AttrPresentDetection(AttrChangedDetection):
   """
   Search if the attribute is present in the data object.
@@ -70,19 +85,25 @@ class ValueChangeFtUpdate(FtUpdate):
     # simple mode, just update the text or the attribute
     new_to_use = converter.convert(new) if converter else new
     if ft_attr is None:
-      if ft.tag == "select":
+      ft.children = (new_to_use,)
-        for child in [c for c in ft.children if c.tag == "option"]:
-          if child.attrs.get("value", None) == new_to_use:
-            child.attrs["selected"] = "true"
-          else:
-            child.attrs.pop("selected", None)
-      else:
-        ft.children = (new_to_use,)
     else:
       ft.attrs[ft_attr] = new_to_use
     return ft
 
 
+class SelectValueChangeFtUpdate(FtUpdate):
+  def update(self, ft, ft_name, ft_attr, old, new, converter):
+    # simple mode, just update the text or the attribute
+    new_to_use = converter.convert(new) if converter else new
+    new_to_use = [new_to_use] if not isinstance(new_to_use, list) else new_to_use
+    for child in [c for c in ft.children if c.tag == "option"]:
+      if child.attrs.get("value", None) in new_to_use:
+        child.attrs["selected"] = "true"
+      else:
+        child.attrs.pop("selected", None)
+    return ft
+
+
 class AttributePresenceFtUpdate(FtUpdate):
   def update(self, ft, ft_name, ft_attr, old, new, converter):
     # attribute presence mode, toggle the attribute (add or remove it)
@@ -198,6 +219,10 @@ class Binding:
       default_data_converter = self.data_converter or RadioConverter(ft.attrs["value"])
       default_detection_mode = DetectionMode.ValueChange
       default_update_mode = UpdateMode.AttributePresence
+    elif is_select(ft):
+      default_data_converter = self.data_converter
+      default_detection_mode = DetectionMode.SelectValueChange
+      default_update_mode = UpdateMode.SelectValueChange
     else:
       default_data_converter = self.data_converter
       default_detection_mode = DetectionMode.ValueChange
@@ -340,12 +365,18 @@ class Binding:
     elif mode == DetectionMode.AttributePresence:
       return AttrPresentDetection(self.ft_name)
     
+    elif mode == DetectionMode.SelectValueChange:
+      return SelectValueChangedDetection(self.ft_name)
+    
     elif mode == UpdateMode.ValueChange:
       return ValueChangeFtUpdate()
     
     elif mode == UpdateMode.AttributePresence:
       return AttributePresenceFtUpdate()
     
+    elif mode == UpdateMode.SelectValueChange:
+      return SelectValueChangeFtUpdate()
+    
     else:
       raise ValueError(f"Invalid detection mode: {mode}")
   

src/myfasthtml/core/utils.py

@@ -125,6 +125,15 @@ def is_radio(elt):
     return False
 
 
+def is_select(elt):
+  if isinstance(elt, (FT, MyFT)):
+    return elt.tag == "select"
+  elif isinstance(elt, Tag):
+    return elt.name == "select"
+  else:
+    return False
+
+
 def quoted_str(s):
   if s is None:
     return "None"

src/myfasthtml/examples/binding_select_multiple.py

@@ -0,0 +1,47 @@
+import logging
+from dataclasses import dataclass
+from typing import Any
+
+from fasthtml import serve
+from fasthtml.components import *
+
+from myfasthtml.controls.helpers import mk
+from myfasthtml.core.bindings import Binding
+from myfasthtml.core.utils import debug_routes
+from myfasthtml.myfastapp import create_app
+
+logging.basicConfig(
+  level=logging.DEBUG,  # Set logging level to DEBUG
+  format='%(asctime)s - %(name)s - %(levelname)s - %(message)s',  # Log format
+  datefmt='%Y-%m-%d %H:%M:%S',  # Timestamp format
+)
+
+app, rt = create_app(protect_routes=False)
+
+
+@dataclass
+class Data:
+  value: Any = "Hello World"
+
+
+data = Data()
+
+
+@rt("/")
+def get():
+  select_elt = Select(
+    Option("Option 1", value="option1"),
+    Option("Option 2", value="option2"),
+    Option("Option 3", value="option3"),
+    name="select_name",
+    multiple=True
+  )
+  label_elt = Label()
+  mk.manage_binding(select_elt, Binding(data), init_binding=False)
+  mk.manage_binding(label_elt, Binding(data))
+  return select_elt, label_elt
+
+
+if __name__ == "__main__":
+  debug_routes(app)
+  serve(port=5002)

src/myfasthtml/test/testclient.py

@@ -325,7 +325,7 @@ class TestableElement:
       
       # Extract all options
       options = []
-      selected_value = None
+      selected_value = []
       
       for option in select_field.find_all('option'):
         option_value = option.get('value', option.get_text(strip=True))
@@ -338,16 +338,20 @@ class TestableElement:
         
         # Track selected option
         if option.has_attr('selected'):
-          selected_value = option_value
+          selected_value.append(option_value)
       
       # Store options list
       self.select_fields[name] = options
       
       # Store selected value (or first option if none selected)
-      if selected_value is not None:
+      is_multiple = select_field.has_attr('multiple')
+      if is_multiple:
         self.fields[name] = selected_value
-      elif options:
+      else:
-        self.fields[name] = options[0]['value']
+        if len(selected_value) > 0:
+          self.fields[name] = selected_value[-1]
+        elif options:
+          self.fields[name] = options[0]['value']
     
     # Process textarea fields
     for textarea_field in self.element.find_all('textarea'):
@@ -783,7 +787,7 @@ class TestableSelect(TestableControl):
         current = [current] if current else []
       if value not in current:
         current.append(value)
-      self.fields[self.name] = current
+      self.fields[self.name] = current[0] if len(current) == 1 else current  # it's not a list when only one is selected
     else:
       # For single select, just set the value
       self.fields[self.name] = value
@@ -835,7 +839,7 @@ class TestableSelect(TestableControl):
     
     if value in current:
       current.remove(value)
-      self.fields[self.name] = current
+      self.fields[self.name] = current[0] if len(current) == 1 else current
       return self._send_value()
     
     return None

tests/controls/test_manage_binding.py

@@ -304,7 +304,109 @@ class TestBindingSelect:
 class TestBindingSelectMultiple:
   """Tests for binding Select components with multiple selection."""
   
-  def test_i_can_bind_select_multiple(self, user, rt):
+  def test_i_can_bind_select_multiple(self):
+    data = Data("")
+    select_elt = Select(
+      Option("Option 1", value="option1"),
+      Option("Option 2", value="option2"),
+      Option("Option 3", value="option3"),
+      name="select_name",
+      multiple=True
+    )
+    
+    binding = Binding(data)
+    updated = mk.manage_binding(select_elt, binding)
+    
+    expected = Select(
+      AttributeForbidden("hx_swap_oob"),
+      Option("Option 1", value="option1"),
+      Option("Option 2", value="option2"),
+      Option("Option 3", value="option3"),
+      name="select_name",
+      id=AnyValue(),
+      hx_post=f"{ROUTE_ROOT}{Routes.Bindings}",
+    )
+    assert matches(updated, expected)
+  
+  def test_i_can_update_one_selection(self):
+    data = Data("")
+    select_elt = Select(
+      Option("Option 1", value="option1"),
+      Option("Option 2", value="option2"),
+      Option("Option 3", value="option3"),
+      name="select_name",
+      multiple=True
+    )
+    
+    binding = Binding(data)
+    mk.manage_binding(select_elt, binding)
+    
+    res = binding.update({"select_name": "option2"})
+    
+    expected = Select(
+      Option("Option 1", value="option1"),
+      Option("Option 2", value="option2", selected="true"),
+      Option("Option 3", value="option3"),
+      name="select_name",
+      id=AnyValue(),
+      hx_post=f"{ROUTE_ROOT}{Routes.Bindings}",
+      hx_swap_oob="true"
+    )
+    assert matches(res, [expected])
+  
+  def test_i_can_update_multiple_selections(self):
+    data = Data("")
+    select_elt = Select(
+      Option("Option 1", value="option1"),
+      Option("Option 2", value="option2"),
+      Option("Option 3", value="option3"),
+      name="select_name",
+      multiple=True
+    )
+    
+    binding = Binding(data)
+    mk.manage_binding(select_elt, binding)
+    
+    res = binding.update({"select_name": ["option2", "option3"]})
+    
+    expected = Select(
+      Option(AttributeForbidden("selected"), "Option 1", value="option1"),
+      Option("Option 2", value="option2", selected="true"),
+      Option("Option 3", value="option3", selected="true"),
+      name="select_name",
+      id=AnyValue(),
+      hx_post=f"{ROUTE_ROOT}{Routes.Bindings}",
+      hx_swap_oob="true"
+    )
+    assert matches(res, [expected])
+  
+  def test_i_can_update_unselect(self):
+    data = Data(["option1", "option2", "option3"])
+    select_elt = Select(
+      Option("Option 1", value="option1", selected="true"),
+      Option("Option 2", value="option2", selected="true"),
+      Option("Option 3", value="option3", selected="true"),
+      name="select_name",
+      multiple=True
+    )
+    
+    binding = Binding(data)
+    mk.manage_binding(select_elt, binding)
+    
+    res = binding.update({})
+    
+    expected = Select(
+      Option(AttributeForbidden("selected"), "Option 1", value="option1"),
+      Option(AttributeForbidden("selected"), "Option 2", value="option2"),
+      Option(AttributeForbidden("selected"), "Option 3", value="option3"),
+      name="select_name",
+      id=AnyValue(),
+      hx_post=f"{ROUTE_ROOT}{Routes.Bindings}",
+      hx_swap_oob="true"
+    )
+    assert matches(res, [expected])
+  
+  def test_i_can_bind_select_multiple_with_label(self, user, rt):
     """
     Multiple select should bind with list data.
     Selecting multiple options should update the label.
@@ -360,7 +462,7 @@ class TestBindingSelectMultiple:
     
     testable_select = user.find_element("select")
     testable_select.deselect("option1")
-    user.should_see("['option2']")
+    user.should_see("option2")
 
 
 class TestBindingRange:

tests/testclient/test_testable_select_multiple.py

@@ -0,0 +1,107 @@
+import pytest
+from fasthtml.fastapp import fast_app
+
+from myfasthtml.test.testclient import TestableSelect, MyTestClient
+
+
+@pytest.fixture
+def test_app():
+  test_app, rt = fast_app(default_hdrs=False)
+  return test_app
+
+
+@pytest.fixture
+def rt(test_app):
+  return test_app.route
+
+
+@pytest.fixture
+def test_client(test_app):
+  return MyTestClient(test_app)
+
+
+def test_i_can_read_select(test_client):
+  html = '''<select name="select_name" multiple>
+  <option value="option1">Option 1</option>
+  <option value="option2">Option 2</option>
+  <option value="option3">Option 3</option>
+  </select>
+  '''
+  select_elt = TestableSelect(test_client, html)
+  assert select_elt.name == "select_name"
+  assert select_elt.value == []
+  assert select_elt.options == [{'text': 'Option 1', 'value': 'option1'},
+                                {'text': 'Option 2', 'value': 'option2'},
+                                {'text': 'Option 3', 'value': 'option3'}]
+  assert select_elt.select_fields == {'select_name': [{'text': 'Option 1', 'value': 'option1'},
+                                                      {'text': 'Option 2', 'value': 'option2'},
+                                                      {'text': 'Option 3', 'value': 'option3'}]}
+  assert select_elt.is_multiple is True
+
+
+def test_i_can_read_select_with_multiple_selected_values(test_client):
+  html = '''<select name="select_name" multiple>
+  <option value="option1" selected>Option 1</option>
+  <option value="option2">Option 2</option>
+  <option value="option3" selected>Option 3</option>
+  </select>
+  '''
+  select_elt = TestableSelect(test_client, html)
+  assert select_elt.name == "select_name"
+  assert select_elt.value == ["option1", "option3"]
+  assert select_elt.is_multiple is True
+
+
+def test_i_can_select_option(test_client):
+  html = '''<select name="select_name" multiple>
+  <option value="option1">Option 1</option>
+  <option value="option2">Option 2</option>
+  <option value="option3">Option 3</option>
+  </select>
+  '''
+  select_elt = TestableSelect(test_client, html)
+  select_elt.select("option2")
+  assert select_elt.value == "option2"
+
+
+def test_i_can_select_multiple_options(test_client):
+  html = '''<select name="select_name" multiple>
+  <option value="option1">Option 1</option>
+  <option value="option2">Option 2</option>
+  <option value="option3">Option 3</option>
+  </select>
+  '''
+  select_elt = TestableSelect(test_client, html)
+  select_elt.select("option2")
+  select_elt.select("option3")
+  assert select_elt.value == ["option2", "option3"]
+
+
+def test_i_can_select_by_text(test_client):
+  html = '''<select name="select_name" multiple>
+  <option value="option1">Option 1</option>
+  <option value="option2">Option 2</option>
+  <option value="option3">Option 3</option>
+  </select>
+  '''
+  select_elt = TestableSelect(test_client, html)
+  select_elt.select_by_text("Option 3")
+  assert select_elt.value == "option3"
+
+
+def test_i_can_deselect(test_client):
+  html = '''<select name="select_name" multiple>
+  <option value="option1" selected>Option 1</option>
+  <option value="option2" selected>Option 2</option>
+  <option value="option3" selected>Option 3</option>
+  </select>
+  '''
+  select_elt = TestableSelect(test_client, html)
+  select_elt.deselect("option3")
+  assert select_elt.value == ["option1", "option2"]
+  
+  select_elt.deselect("option2")
+  assert select_elt.value == "option1"
+  
+  select_elt.deselect("option1")
+  assert select_elt.value == []