Simple event manager for Lua.

eventManager.lua

local eventManager <const> = {}

function addEventListener(eventName, listener)
    local eventListeners = eventManager[eventName]

    if not eventListeners then
        eventListeners = {}
        eventManager[eventName] = eventListeners
    end

    table.insert(eventListeners, listener)
end

function invokeEvent(eventName, ...)
    local eventListeners = eventManager[eventName]

    if not eventListeners then
        return
    end

    for _, listener in ipairs(eventListeners) do
        listener(...)
    end
end

function removeEventListener(eventName, listener)
    local eventListeners = eventManager[eventName]

    if not eventListeners then
        return
    end

    for i = 1, #eventListeners do
        if eventListeners[i] == listener then
            table.remove(eventListeners, i)
            return
        end
    end
end