wip: ideas on generic validation

eslint.config.js

@@ -1,9 +1,9 @@
-import globals from "globals";
 import pluginJs from "@eslint/js";
-import tseslint from "typescript-eslint";
-import pluginReact from "eslint-plugin-react";
 import eslintConfigPrettier from "eslint-config-prettier";
 import pluginImport from "eslint-plugin-import";
+import pluginReact from "eslint-plugin-react";
+import globals from "globals";
+import tseslint from "typescript-eslint";
 
 export default [
   { files: ["**/*.{js,mjs,cjs,ts,jsx,tsx}"] },

lonboard/_map.py

@@ -9,6 +9,7 @@
 import traitlets as t
 from ipywidgets import CallbackDispatcher
 
+from lonboard import _validators as validators
 from lonboard._base import BaseAnyWidget
 from lonboard._html_export import map_to_html
 from lonboard._layer import BaseLayer
@@ -20,13 +21,15 @@
     VariableLengthTuple,
     ViewStateTrait,
 )
+from lonboard.view import BaseView
 
 if TYPE_CHECKING:
     import sys
     from collections.abc import Callable, Sequence
 
     from IPython.display import HTML  # type: ignore
 
+    from lonboard._validators.types import TraitProposal
     from lonboard.types.map import MapKwargs
 
     if sys.version_info >= (3, 12):
@@ -151,6 +154,8 @@ def on_click(self, callback: Callable, *, remove: bool = False) -> None:
     _esm = bundler_output_dir / "index.js"
     _css = bundler_output_dir / "index.css"
 
+    # TODO: change this view state to allow non-map view states if we have non-map views
+    # Also allow a list/tuple of view states for multiple views
     view_state = ViewStateTrait()
     """
     The view state of the map.
@@ -174,6 +179,14 @@ def on_click(self, callback: Callable, *, remove: bool = False) -> None:
         once it's been initially rendered.
 
     """
+
+    @t.validate("view_state")
+    def _validate_view_state(
+        self,
+        proposal: TraitProposal[ViewStateTrait, dict[str, Any], Map],
+    ) -> dict[str, Any] | None:
+        return validators.map.validate_view_state(proposal)
+
     _has_click_handlers = t.Bool(default_value=False, allow_none=False).tag(sync=True)
     """
     Indicates if a click handler has been registered.
@@ -192,6 +205,15 @@ def on_click(self, callback: Callable, *, remove: bool = False) -> None:
     """One or more `Layer` objects to display on this map.
     """
 
+    views: t.Instance[BaseView | None] = t.Instance(BaseView, allow_none=True).tag(
+        sync=True,
+        **ipywidgets.widget_serialization,
+    )
+    """A View instance.
+
+    Views represent the "camera(s)" (essentially viewport dimensions and projection matrices) that you look at your data with. deck.gl offers multiple view types for both geospatial and non-geospatial use cases. Read the [Views and Projections](https://deck.gl/docs/developer-guide/views) guide for the concept and examples.
+    """
+
     show_tooltip = t.Bool(default_value=False).tag(sync=True)
     """
     Whether to render a tooltip on hover on the map.
@@ -221,6 +243,9 @@ def on_click(self, callback: Callable, *, remove: bool = False) -> None:
 
     basemap: t.Instance[MaplibreBasemap | None] = t.Instance(
         MaplibreBasemap,
+        # If both `args` and `kw` are None, then the default value is None.
+        # Set empty kw so that the default is MaplibreBasemap() with default params
+        kw={},
         allow_none=True,
     ).tag(
         sync=True,

lonboard/_validators/__init__.py

@@ -0,0 +1 @@
+from . import map  # noqa: A004

lonboard/_validators/map.py

@@ -0,0 +1,17 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from typing import Any
+
+    from lonboard import Map
+    from lonboard._validators.types import TraitProposal
+    from lonboard.traits import ViewStateTrait
+
+
+def validate_view_state(
+    proposal: TraitProposal[ViewStateTrait, dict[str, Any], Map],
+) -> dict[str, Any] | None:
+    """Validate the view_state trait of a Map instance."""
+    return proposal["value"]

lonboard/_validators/types.py

@@ -0,0 +1,20 @@
+from __future__ import annotations
+
+from typing import Generic, TypedDict, TypeVar
+
+from traitlets import HasTraits, TraitType
+
+Trait = TypeVar("Trait", bound=TraitType)
+Value = TypeVar("Value")
+Owner = TypeVar("Owner", bound=HasTraits)
+
+
+class TraitProposal(TypedDict, Generic[Trait, Value, Owner]):
+    """The type of a traitlets proposal.
+
+    The input into a `@validate` method.
+    """
+
+    trait: Trait
+    value: Value
+    owner: Owner

lonboard/traits.py

@@ -47,6 +47,7 @@
     from traitlets.utils.sentinel import Sentinel
 
     from lonboard._layer import BaseArrowLayer
+    from lonboard._map import Map
 
 DEFAULT_INITIAL_VIEW_STATE = {
     "latitude": 10,
@@ -943,7 +944,7 @@ def __init__(
 
         self.tag(sync=True, to_json=serialize_view_state)
 
-    def validate(self, obj: Any, value: Any) -> None | ViewState:
+    def validate(self, obj: Map, value: Any) -> None | ViewState:
         if value is None:
             return None
 

lonboard/types/map.py

@@ -10,6 +10,7 @@
 
 if TYPE_CHECKING:
     from lonboard.basemap import MaplibreBasemap
+    from lonboard.view import BaseView
 
 
 class MapKwargs(TypedDict, total=False):
@@ -22,4 +23,5 @@ class MapKwargs(TypedDict, total=False):
     show_tooltip: bool
     show_side_panel: bool
     use_device_pixels: int | float | bool
+    views: BaseView | list[BaseView] | tuple[BaseView, ...]
     view_state: dict[str, Any]