ObservableValue

A typed value you can read, set, and observe. Adding a listener returns a cleanup function that's safe to call more than once.

Full API reference at jdevon.github.io/observable-value.

Install

Install with Wally by adding it to your wally.toml:

[dependencies]
ObservableValue = "jdevon/observable-value@0.1.0"

Usage

local ObservableValue = require(ReplicatedStorage.Packages.ObservableValue)

local health = ObservableValue.new(100)

local cleanup = health:onChanged(function(newHealth, oldHealth)
	print(`health went from {oldHealth} to {newHealth}`)
end)

health:set(80) --> health went from 100 to 80
health:update(function(current)
	return current - 10
end) --> health went from 80 to 70

cleanup()

-- yields until health drops to 0 or below, then continues with the final value
local finalHealth = health:promiseValue(function(current)
	return current <= 0, current
end):expect()
print(`defeated at {finalHealth} health`)

API

Each member links to its full entry in the API reference.

Types

• Disconnect - the cleanup function returned by every listener method

Properties

• version - increases each time the value changes

Functions

• .new - creates an ObservableValue holding an initial value
• :get - returns the current value
• :set - sets the value
• :update - sets the value from the current one
• :onChanged - calls back whenever the value changes
• :onSet - calls back on every set
• :observe - calls back now with the current value, then on every change
• :promiseValue - resolves once the value passes a check
• :Destroy - disconnects every listener (:destroy also works)