Observer graph object since v0.2 ¶

Observes various updates and events on a given dependency.

(
    observe: Dependency
) -> Observer

Parameters¶

observe: Dependency - the dependency this observer should respond to

Object Methods¶

since v0.2

Observer:onChange()¶

Connects the given callback as a change handler, and returns a function which will disconnect the callback. The callback will run whenever the observed dependency is updated.

(callback: () -> ()) -> (() -> ())

Parameters¶

callback - The function to call when a change is observed

Connection memory leaks

Make sure to disconnect any change handlers made using this function once you're done using them.

As long as a change handler is connected, this observer and the dependency it observes will be held in memory in case further changes occur. This means, if you don't call the disconnect function, you may end up accidentally holding your state objects in memory forever after you're done using them.

Example Usage¶

local numCoins = Value(50)

local coinObserver = Observer(numCoins)

local disconnect = coinObserver:onChange(function()
    print("coins is now:", numCoins:get())
end)

numCoins:set(25) -- prints 'coins is now: 25'

-- always clean up your connections!
disconnect()