Typing

Typing¶

The codebase uses type hints and aims for clarity over cleverness.

Guidelines:

Prefer precise types on public APIs; avoid Any.
Use Optional[...] where values can be absent.
In Pyodide/browser interop, tolerate Any at boundaries but narrow types internally.

mypy configuration¶

Config is in mypy.ini targeting Python 3.9. Browser shims (e.g., js, pyodide) are marked as ignore_missing_imports.
Run mypy against src, tests, examples, bench per config.

Examples¶

Reactivity API
signal(value) -> Signal[T]
computed(fn: Callable[[], T]) -> _Computed[T]
effect(fn: Callable[[], Any]) -> Computation
use_resource(fetcher: Callable[..., Awaitable[R]]) -> Resource[R]

from typing import Awaitable
from wybthon import signal, computed, effect, use_resource

count = signal(0)
double = computed(lambda: count.get() * 2)

def log() -> None:
    _ = double.get()  # subscribes

c = effect(log)      # Computation
c.dispose()          # stop updates

async def fetch_user() -> dict:
    return {"name": "Ada"}

res = use_resource(cast(Callable[[], Awaitable[dict]], fetch_user))

Component typing
Component.render(self) -> VNode
Function components: def MyComp(props: Dict[str, Any]) -> VNode

from typing import Any, Dict
from wybthon import Component, h, VNode

class Hello(Component):
    def render(self) -> VNode:
        name = self.props.get("name", "world")
        return h("div", {}, f"Hello {name}")

def HelloFn(props: Dict[str, Any]) -> VNode:
    return h("div", {}, f"Hello {props.get('name', 'world')}")

Router types
Route(path: str, component: Union[Callable[[Dict[str, Any]], VNode], type])
navigate(path: str, replace: bool = False) -> None

from typing import Any, Dict
from wybthon import Route, Router, h

routes = [
    Route(path="/", component=lambda _props: h("div", {}, "Home")),
]