Extensions

Extensions observe a Component's lifecycle without touching the Component's own class, the tool for cross-cutting behavior (logging, analytics, debug tooling) that would otherwise mean copy-pasting the same print calls into every Component's Construct/Start/Destroy.

Available hooks (in execution order)

Creating and attaching an extension

local Component = Owl.Util.Component
 
-- > // Create an extension
local LogExtension = Component.CreateExtension({
    Name = "Logger",
    Hooks = {
        Constructed = function(comp)
            print(("[LOG] %s, Construct done"):format(comp.Instance.Name))
        end,
 
        Stopped = function(comp)
            print(("[LOG] %s, Destroyed"):format(comp.Instance.Name))
        end,
    },
})
 
-- > // Attach it to a Component
local EnemyComponent = Component.new({
    Tag = "Enemy",
    Type = "Server",
    Extensions = { LogExtension },
})

The same extension can be attached to as many Component types as you want LogExtension above would work identically on an ItemComponent or a NPCComponent, since every hook receives the Component instance itself (comp) rather than assuming anything about which Component it's attached to.

An extension that throws inside a hook doesn't stop other extensions from running. The error is caught and shown as a warning instead, one misbehaving Logger extension can't take down whatever a Metrics extension attached to the same Component is doing.

Where to go next

• Creating a Component - the Construct/Start/Destroy lifecycle these hooks wrap around.
• API Reference - the full signature for Component.CreateExtension and every Component option.