-- used to retrieve NPC name using their ID (localized)
local tip = CreateFrame("GameTooltip")
tip.txt = tip:CreateFontString()
tip:AddFontStrings(tip.txt, tip:CreateFontString())
function tip:name(id)
  tip:SetOwner(WorldFrame, "ANCHOR_NONE")
  tip:SetHyperlink(("unit:0xF53%05X00000000"):format(id))
  return tip:IsShown() and tip.txt:GetText()
end
 
-- the events we wish to apply our filter on
local events = {
  "CHAT_MSG_MONSTER_EMOTE",
  "CHAT_MSG_MONSTER_PARTY",
  "CHAT_MSG_MONSTER_SAY",
  "CHAT_MSG_MONSTER_WHISPER",
  "CHAT_MSG_MONSTER_YELL",
}
 
-- list of npcIDs we are to ignore
local database = {
  ["34692"] = 1, -- Sister Goldskimmer (each time she buffs)
  ["34695"] = 1, -- Maxx Avalanche
  ["34835"] = 1,
  ["34876"] = 1,
  ["34877"] = 1,
  ["34878"] = 1,
  ["35120"] = 1,
  ["35175"] = 1,
  ["37106"] = 1,
}
 
-- will be populated later on
local ignore = {}
local rescan = {}
 
-- scans the table of npcIDs and populates the above (empty) tables
local function scanTable(tbl)
  for npcid, _ in pairs(tbl) do
    local npcname = tip:name(npcid)
    if npcname then
      ignore[npcname] = 1 -- the npc is cached, we add it's name to the ignore list
      rescan[npcid] = nil -- remove from the re-scan list (if it's there)
    else
      rescan[npcid] = 1 -- not cached yet so we add the id to the "to-rescan-later" list
    end
  end
end
 
-- process the database
scanTable(database)
 
-- decides if message should be hidden or not
local function filter(self, event, msg, sender, ...)
  scanTable(rescan) -- we scan leftovers on filter triggers
  return ignore[sender] and true or false
end
 
-- register our filter with the chat frames
for _, event in pairs(events) do
  ChatFrame_AddMessageEventFilter(event, filter)
end