EVENT_EFFECT_CHANGED

Official signature

EVENT_EFFECT_CHANGED([EffectResult|#EffectResult] changeType, integer effectSlot, string effectName, string unitTag, number beginTime, number endTime, integer stackCount, string iconName, string deprecatedBuffType, [BuffEffectType|#BuffEffectType] effectType, [AbilityType|#AbilityType] abilityType, [StatusEffectType|#StatusEffectType] statusEffectType, string unitName, integer unitId, integer abilityId, [CombatUnitType|#CombatUnitType] sourceType)

Real usage — from Combat Metrics

	self.effectType = effectType -- buff or debuff
	self.maxStacks = 0 -- stacks = 0 if the effect wasn't tracked trough EVENT_EFFECT_CHANGED
	self.firstStartTime = nil -- temp variable to track when uptime for a buff initially started

Short excerpt from the shipping addon Combat Metrics — its ESOUI page; the code belongs to its author. Shown because documentation without a working example is half a reference.

Most-downloaded addons using it