Change Events

OnChange is a function that returns keys to use when hydrating or creating an instance. Those keys let you connect functions to property changed events on the instance.

local input = scope:New "TextBox" {
    [OnChange "Text"] = function(newText)
        print("You typed:", newText)
    end
}

---

Usage

OnChange doesn't need a scope - import it into your code from Fusion directly.

local OnChange = Fusion.OnChange

When you call OnChange with a property name, it will return a special key:

local key = OnChange("Text")

When used in a property table, you can pass in a handler and it will be run when that property changes.

Arguments are different to Roblox API

Normally in the Roblox API, when using :GetPropertyChangedSignal() on an instance, the callback will not receive any arguments.

To make working with change events easier, OnChange will pass the new value of the property to the callback.

local input = scope:New "TextBox" {
    [OnChange("Text")] = function(newText)
        print("You typed:", newText)
    end
}

If you're using quotes '' "" for the event name, the extra parentheses () are optional:

local input = scope:New "TextBox" {
    [OnChange "Text"] = function(newText)
        print("You typed:", newText)
    end
}