Primitives

Primitives

Wybthon uses a signals-first reactive model inspired by SolidJS. Components can be stateless (return a VNode directly) or stateful (create signals during a one-time setup phase and return a render function that re-runs automatically when signals change).

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create_signal

Create a reactive signal. Returns (getter, setter).

from wybthon import component, create_signal, div, p

@component
def Counter(initial: int = 0):
    count, set_count = create_signal(initial)

    def render():
        return div(
            p(f"Count: {count()}"),
        )
    return render

The setter accepts a plain value:

set_count(42)

Signals created during setup persist for the lifetime of the component -- no cursor system, no "rules of hooks".

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create_effect

Create an auto-tracking reactive effect. The effect runs immediately and re-runs whenever any signal it reads changes.

from wybthon import component, create_effect, create_signal

@component
def Logger():
    count, set_count = create_signal(0)

    create_effect(lambda: print("count is now", count()))

    def render():
        return ...
    return render

Use on_cleanup inside a create_effect callback to register cleanup that runs before each re-execution and on disposal:

def tracked():
    val = count()
    on_cleanup(lambda: print(f"cleaning up for {val}"))

create_effect(tracked)

---

create_memo

Create an auto-tracking computed value. Returns a getter function that re-computes only when its dependencies change.

doubled = create_memo(lambda: count() * 2)
print(doubled())  # reactive read

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on_mount

Register a callback to run once after the component mounts.

from wybthon import component, on_mount

@component
def MyComponent():
    on_mount(lambda: print("Component is in the DOM!"))

    def render():
        return ...
    return render

---

on_cleanup

Register a cleanup callback.

• Inside a component's setup phase: runs when the component unmounts.
• Inside a create_effect callback: runs before each re-execution and on disposal.

from wybthon import component, on_cleanup, on_mount

@component
def Timer():
    on_mount(lambda: start_timer())
    on_cleanup(lambda: stop_timer())

    def render():
        return ...
    return render

---

get_props

Return a reactive getter for the current component's props. Useful in stateful components that need to react when a parent changes props:

from wybthon import component, create_effect, get_props

@component
def Search(query: str = ""):
    props = get_props()
    create_effect(lambda: print("query changed:", props()["query"]))

    def render():
        return ...
    return render

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Primitives vs. class components

	@component + primitives	Class component
State	create_signal	self.count = signal(0)
Side effects	create_effect / on_mount	on_mount / on_cleanup
Computed	create_memo	computed(lambda: ...)

Both styles are fully supported; choose whichever fits your situation. For new code, @component with signals-first primitives is recommended.