Skip to content

Nuiitivet Documentation

Basic API

yuksblog/nuiitivet

Observable: Basic API¶

Creating an Observable¶

import nuiitivet.material as nv

name = nv.Observable("Alice")
age = nv.Observable(20)
items = nv.Observable([])

Getting and Setting Values¶

current = age.value
age.value = 21

Writing from a lambda¶

age.value = 21 is a statement, and a Python lambda can only hold an expression — so it cannot be used in a callback prop or a subscribe lambda. set() is the same write in expression form:

nv.Button("Increment", on_click=lambda: age.set(age.value + 1))

Use .value = wherever a statement fits; reach for set() only where one does not. Both go through the identical write path, so equality de-duping, compare, batching and thread dispatch behave the same either way.

Subscribing and Unsubscribing¶

subscription = age.subscribe(lambda value: print(value))
subscription.dispose()

In most UI cases, cleanup is handled automatically by the framework lifecycle.

Custom Comparison Function¶

By default, value equality uses ==.

count = nv.Observable(0)

You can customize comparison behavior when needed.

always_notify = nv.Observable(0, compare=lambda a, b: False)

def compare_users(a, b):
    if a is None or b is None:
        return a is b
    return a.uid == b.uid

user = nv.Observable(None, compare=compare_users)

Next Steps¶