introduce IconElement mixin

nicegui/elements/avatar.py

@@ -1,9 +1,10 @@
 from typing import Optional
 
 from .mixins.color_elements import BackgroundColorElement, TextColorElement
+from .mixins.icon_element import IconElement
 
 
-class Avatar(BackgroundColorElement, TextColorElement):
+class Avatar(IconElement, BackgroundColorElement, TextColorElement):
     TEXT_COLOR_PROP = 'text-color'
 
     def __init__(self,
@@ -28,10 +29,8 @@ def __init__(self,
         :param square: removes border-radius so borders are squared (default: False)
         :param rounded: applies a small standard border-radius for a squared shape of the component (default: False)
         """
-        super().__init__(tag='q-avatar', background_color=color, text_color=text_color)
+        super().__init__(tag='q-avatar', background_color=color, text_color=text_color, icon=icon)
 
-        if icon is not None:
-            self._props['icon'] = icon
         self._props['square'] = square
         self._props['rounded'] = rounded
 

nicegui/elements/button.py

@@ -6,10 +6,11 @@
 from ..events import ClickEventArguments, handle_event
 from .mixins.color_elements import BackgroundColorElement
 from .mixins.disableable_element import DisableableElement
+from .mixins.icon_element import IconElement
 from .mixins.text_element import TextElement
 
 
-class Button(TextElement, DisableableElement, BackgroundColorElement):
+class Button(IconElement, TextElement, DisableableElement, BackgroundColorElement):
 
     def __init__(self,
                  text: str = '', *,
@@ -31,10 +32,7 @@ def __init__(self,
         :param color: the color of the button (either a Quasar, Tailwind, or CSS color or `None`, default: 'primary')
         :param icon: the name of an icon to be displayed on the button (default: `None`)
         """
-        super().__init__(tag='q-btn', text=text, background_color=color)
-
-        if icon:
-            self._props['icon'] = icon
+        super().__init__(tag='q-btn', text=text, background_color=color, icon=icon)
 
         if on_click:
             self.on_click(on_click)

nicegui/elements/button_dropdown.py

@@ -3,11 +3,12 @@
 from ..events import ClickEventArguments, handle_event
 from .mixins.color_elements import BackgroundColorElement
 from .mixins.disableable_element import DisableableElement
+from .mixins.icon_element import IconElement
 from .mixins.text_element import TextElement
 from .mixins.value_element import ValueElement
 
 
-class DropdownButton(TextElement, DisableableElement, BackgroundColorElement, ValueElement):
+class DropdownButton(IconElement, TextElement, DisableableElement, BackgroundColorElement, ValueElement):
 
     def __init__(self,
                  text: str = '', *,
@@ -38,10 +39,7 @@ def __init__(self,
         :param split: whether to split the dropdown icon into a separate button (default: `False`)
         """
         super().__init__(tag='q-btn-dropdown',
-                         text=text, background_color=color, value=value, on_value_change=on_value_change)
-
-        if icon:
-            self._props['icon'] = icon
+                         icon=icon, text=text, background_color=color, value=value, on_value_change=on_value_change)
 
         if auto_close:
             self._props['auto-close'] = True

nicegui/elements/chip.py

@@ -5,12 +5,13 @@
 from ..events import ClickEventArguments, handle_event
 from .mixins.color_elements import BackgroundColorElement, TextColorElement
 from .mixins.disableable_element import DisableableElement
+from .mixins.icon_element import IconElement
 from .mixins.selectable_element import SelectableElement
 from .mixins.text_element import TextElement
 from .mixins.value_element import ValueElement
 
 
-class Chip(ValueElement, TextElement, BackgroundColorElement, TextColorElement, DisableableElement, SelectableElement):
+class Chip(IconElement, ValueElement, TextElement, BackgroundColorElement, TextColorElement, DisableableElement, SelectableElement):
     TEXT_COLOR_PROP = 'text-color'
 
     def __init__(self,
@@ -43,10 +44,8 @@ def __init__(self,
         :param on_value_change: callback which is invoked when the chip is removed or unremoved
         """
         super().__init__(tag='q-chip', value=True, on_value_change=on_value_change,
-                         text=text, text_color=text_color, background_color=color,
+                         icon=icon, text=text, text_color=text_color, background_color=color,
                          selectable=selectable, selected=selected, on_selection_change=on_selection_change)
-        if icon:
-            self._props['icon'] = icon
 
         self._props['removable'] = removable
 

nicegui/elements/expansion.py

@@ -1,11 +1,12 @@
 from typing import Any, Callable, Optional
 
 from .mixins.disableable_element import DisableableElement
+from .mixins.icon_element import IconElement
 from .mixins.text_element import TextElement
 from .mixins.value_element import ValueElement
 
 
-class Expansion(TextElement, ValueElement, DisableableElement):
+class Expansion(IconElement, TextElement, ValueElement, DisableableElement):
 
     def __init__(self,
                  text: str = '', *,
@@ -26,12 +27,11 @@ def __init__(self,
         :param value: whether the expansion should be opened on creation (default: `False`)
         :param on_value_change: callback to execute when value changes
         """
-        super().__init__(tag='q-expansion-item', text=text, value=value, on_value_change=on_value_change)
+        super().__init__(tag='q-expansion-item', icon=icon, text=text, value=value, on_value_change=on_value_change)
         if caption is not None:
             self._props['caption'] = caption
         if group is not None:
             self._props['group'] = group
-        self._props['icon'] = icon
         self._classes.append('nicegui-expansion')
 
     def open(self) -> None:

nicegui/elements/mixins/icon_element.py

@@ -0,0 +1,89 @@
+from typing import Any, Callable, Optional, cast
+
+from typing_extensions import Self
+
+from ...binding import BindableProperty, bind, bind_from, bind_to
+from ...element import Element
+
+
+class IconElement(Element):
+    icon = BindableProperty(
+        on_change=lambda sender, icon: cast(Self, sender)._handle_icon_change(icon))  # pylint: disable=protected-access
+
+    def __init__(self, *, icon: Optional[str] = None, **kwargs: Any) -> None:  # pylint: disable=redefined-builtin
+        super().__init__(**kwargs)
+        self.icon = icon
+        if icon is not None:
+            self._props['icon'] = icon
+
+    def bind_icon_to(self,
+                     target_object: Any,
+                     target_name: str = 'icon',
+                     forward: Callable[..., Any] = lambda x: x,
+                     ) -> Self:
+        """Bind the icon of this element to the target object's target_name property.
+
+        The binding works one way only, from this element to the target.
+        The update happens immediately and whenever a value changes.
+
+        :param target_object: The object to bind to.
+        :param target_name: The name of the property to bind to.
+        :param forward: A function to apply to the value before applying it to the target.
+        """
+        bind_to(self, 'icon', target_object, target_name, forward)
+        return self
+
+    def bind_icon_from(self,
+                       target_object: Any,
+                       target_name: str = 'icon',
+                       backward: Callable[..., Any] = lambda x: x,
+                       ) -> Self:
+        """Bind the icon of this element from the target object's target_name property.
+
+        The binding works one way only, from the target to this element.
+        The update happens immediately and whenever a value changes.
+
+        :param target_object: The object to bind from.
+        :param target_name: The name of the property to bind from.
+        :param backward: A function to apply to the value before applying it to this element.
+        """
+        bind_from(self, 'icon', target_object, target_name, backward)
+        return self
+
+    def bind_icon(self,
+                  target_object: Any,
+                  target_name: str = 'icon', *,
+                  forward: Callable[..., Any] = lambda x: x,
+                  backward: Callable[..., Any] = lambda x: x,
+                  ) -> Self:
+        """Bind the icon of this element to the target object's target_name property.
+
+        The binding works both ways, from this element to the target and from the target to this element.
+        The update happens immediately and whenever a value changes.
+        The backward binding takes precedence for the initial synchronization.
+
+        :param target_object: The object to bind to.
+        :param target_name: The name of the property to bind to.
+        :param forward: A function to apply to the value before applying it to the target.
+        :param backward: A function to apply to the value before applying it to this element.
+        """
+        bind(self, 'icon', target_object, target_name, forward=forward, backward=backward)
+        return self
+
+    def set_icon(self, icon: Optional[str]) -> None:
+        """Set the icon of this element.
+
+        :param icon: The new icon.
+        """
+        self.icon = icon
+
+    def _handle_icon_change(self, icon: Optional[str]) -> None:
+        """Called when the icon of this element changes.
+
+        :param icon: The new icon.
+        """
+        if icon is not None:
+            self._props['icon'] = icon
+        else:
+            self._props.pop('icon', None)
+        self.update()

nicegui/elements/stepper.py

@@ -5,6 +5,7 @@
 from ..context import context
 from ..element import Element
 from .mixins.disableable_element import DisableableElement
+from .mixins.icon_element import IconElement
 from .mixins.value_element import ValueElement
 
 
@@ -51,7 +52,7 @@ def previous(self) -> None:
         self.run_method('previous')
 
 
-class Step(DisableableElement):
+class Step(IconElement, DisableableElement):
 
     def __init__(self, name: str, title: Optional[str] = None, icon: Optional[str] = None) -> None:
         """Step
@@ -63,12 +64,10 @@ def __init__(self, name: str, title: Optional[str] = None, icon: Optional[str] =
         :param title: title of the step (default: `None`, meaning the same as `name`)
         :param icon: icon of the step (default: `None`)
         """
-        super().__init__(tag='q-step')
+        super().__init__(tag='q-step', icon=icon)
         self._props['name'] = name
         self._props['title'] = title if title is not None else name
         self._classes.append('nicegui-step')
-        if icon:
-            self._props['icon'] = icon
         self.stepper = cast(ValueElement, context.slot.parent)
         if self.stepper.value is None:
             self.stepper.value = name

nicegui/elements/tabs.py

@@ -4,6 +4,7 @@
 
 from ..context import context
 from .mixins.disableable_element import DisableableElement
+from .mixins.icon_element import IconElement
 from .mixins.value_element import ValueElement
 
 
@@ -27,7 +28,7 @@ def _value_to_model_value(self, value: Any) -> Any:
         return value._props['name'] if isinstance(value, (Tab, TabPanel)) else value  # pylint: disable=protected-access
 
 
-class Tab(DisableableElement):
+class Tab(IconElement, DisableableElement):
 
     def __init__(self, name: str, label: Optional[str] = None, icon: Optional[str] = None) -> None:
         """Tab
@@ -39,11 +40,9 @@ def __init__(self, name: str, label: Optional[str] = None, icon: Optional[str] =
         :param label: label of the tab (default: `None`, meaning the same as `name`)
         :param icon: icon of the tab (default: `None`)
         """
-        super().__init__(tag='q-tab')
+        super().__init__(tag='q-tab', icon=icon)
         self._props['name'] = name
         self._props['label'] = label if label is not None else name
-        if icon:
-            self._props['icon'] = icon
         self.tabs = context.slot.parent
 
 

nicegui/elements/teleport.py

@@ -1,6 +1,6 @@
 from typing import Union
 
-from nicegui.element import Element
+from ..element import Element
 
 
 class Teleport(Element, component='teleport.js'):

nicegui/elements/timeline.py

@@ -1,6 +1,7 @@
 from typing import Literal, Optional
 
-from nicegui.element import Element
+from ..element import Element
+from .mixins.icon_element import IconElement
 
 
 class Timeline(Element):
@@ -26,7 +27,7 @@ def __init__(self,
             self._props['color'] = color
 
 
-class TimelineEntry(Element):
+class TimelineEntry(IconElement):
 
     def __init__(self,
                  body: Optional[str] = None,
@@ -54,7 +55,7 @@ def __init__(self,
         :param subtitle: Subtitle text.
         :param color: Color or the timeline.
         """
-        super().__init__('q-timeline-entry')
+        super().__init__(tag='q-timeline-entry', icon=icon)
         if body is not None:
             self._props['body'] = body
         self._props['side'] = side
@@ -63,8 +64,6 @@ def __init__(self,
             self._props['tag'] = tag
         if color is not None:
             self._props['color'] = color
-        if icon is not None:
-            self._props['icon'] = icon
         if avatar is not None:
             self._props['avatar'] = avatar
         if title is not None: