From 1e4132be21b56e47f878251bf6d02652e46222dd Mon Sep 17 00:00:00 2001
From: Brandon Blanker Lim-it <flamendless8@gmail.com>
Date: Tue, 14 Feb 2023 18:18:43 -0300
Subject: [PATCH] Added beforeEmit and afterEmit World callbacks (#54)

* Added beforeEmit and afterEmit World callbacks

* Fixed beforeEmit/afterEmit to handle recursive/nested emits;

* Added preventDefaults in beforeEmit
---
 concord/world.lua | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/concord/world.lua b/concord/world.lua
index 7008da4..7b31a6e 100644
--- a/concord/world.lua
+++ b/concord/world.lua
@@ -52,6 +52,8 @@ function World.new()
       __systemLookup = {},
 
       __isWorld = true,
+
+      __ignoreEmits = false
    }, World.__mt)
 
    -- Optimization: We deep copy the World class into our instance of a world.
@@ -320,7 +322,14 @@ function World:emit(functionName, ...)
 
    self.__emitSDepth = self.__emitSDepth + 1
 
-	local listeners = self.__events[functionName]
+   local listeners = self.__events[functionName]
+
+   if not self.__ignoreEmits and Type.isCallable(self.beforeEmit) then
+      self.__ignoreEmits = true
+      local preventDefaults = self:beforeEmit(functionName, listeners, ...)
+      self.__ignoreEmits = false
+      if preventDefaults then return end
+   end
 
    if listeners then
       for i = 1, #listeners do
@@ -336,6 +345,12 @@ function World:emit(functionName, ...)
       end
    end
 
+   if not self.__ignoreEmits and Type.isCallable(self.afterEmit) then
+      self.__ignoreEmits = true
+      self:afterEmit(functionName, listeners, ...)
+      self.__ignoreEmits = false
+   end
+
    self.__emitSDepth = self.__emitSDepth - 1
 
    return self