lazy-signals 0.2.0

running effects on value updates with dependency discovery - conceptually inspired by Signal in JavaScript

Lazy Signals 🪢

lazysignals is a Python library that runs effects whenever state changes. It employs dependency discovery and updates are lazy. The library is conceptually inspired by signals in JavaScript.

Please checkout our latest documentation.

Example

The framework runs relevant effects whenever some state changes:

define a new signal s, holding the initial value 1

s = Signal(1)

derive a signal that checks the parity of s

p = derived(lambda: s.value % 2 == 0)

log the parity p to the console

effect(lambda: print(f"parity:", "even" if p.value else "odd"))

perform some updates to s

s.value = 1  # no change, no output
s.value = 2  # output: "parity: even"
s.value = 3  # output: "parity: odd"
s.value = 5  # no change, no output
s.value = 6  # output: "parity: even"

Have a look at example.py for more; run with pipenv install (to locally install this library) and pipenv run example.