From fa58e719d5fb5515e00f765f79fe920e4cb996fe Mon Sep 17 00:00:00 2001
From: Elias Fleckenstein <eliasfleckenstein@web.de>
Date: Fri, 6 Aug 2021 23:19:34 +0200
Subject: Add Event and EventTarget

---
 events.lua | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 events.lua

(limited to 'events.lua')

diff --git a/events.lua b/events.lua
new file mode 100644
index 0000000..ee723e8
--- /dev/null
+++ b/events.lua
@@ -0,0 +1,61 @@
+local EventPrototype = {}
+
+function EventPrototype:preventDefault()
+	self.defaultPrevented = true
+end
+
+function Event(type, data)
+	return setmetatable({
+		type = type,
+		data = data,
+		defaultPrevented = false,
+		timeStamp = os.clock(),
+	}, {__index = EventPrototype})
+end
+
+local EventTargetPrototype = {}
+
+function EventTargetPrototype:dispatchEvent(event)
+	event.target = self
+
+	local callback = self["on" + event.type]
+
+	if callback then
+		callback(event)
+	end
+
+	local listeners = self.__eventListeners[type]
+
+	if listeners then
+		for i, callback in ipairs(listeners) do
+			callback(event)
+		end
+	end
+
+	return not event.defaultPrevented
+end
+
+function EventTargetPrototype:addEventListener(type, callback)
+	local listeners = self.__eventListeners[type] or {}
+	table.insert(listeners, callback)
+	self.__eventListeners[type] = listeners
+end
+
+function EventTargetPrototype:removeEventListener(type, callback)
+	local listeners = self.__eventListeners[type]
+
+	if listeners then
+		for k, v in pairs(listeners) do
+			if v == callback then
+				table.remove(listeners, k)
+				break
+			end
+		end
+	end
+end
+
+function EventTarget()
+	return setmetatable({
+		__eventListeners = {},
+	}, {__index = EventTargetPrototype})
+end
-- 
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