5.19.3

Add methods to the states/allstates table that helps with creating,
updating or remove states in an optimized way

## Advantage of using this function instead of doing a states[key] = {
... }

- If already created, update existing state, and return true if any
value was changed, this can help reduce amount of resources an aura use

- Automatically `return true` when using these functions and any change
was made

## Examples

```Lua
function(states, event, ...)
    if event == "PLAYER_TARGET_CHANGED" then
        if UnitExists("target") then
            -- if state exists it's updated, not replaced
            -- show & changed fields can be skipped
            states:Update("", {
                    name = UnitName("target"),
                    duration = 5,
                    expirationTime = GetTime() + 5,
                    progressType = "timed",
                    autoHide = true
            })
        else
            -- wipe
            states:RemoveAll()
        end
    end
    -- no need to return true
end
```

with clones

```Lua
function(states, event, ...)
    local currentEssence = UnitPower("player", Enum.PowerType.Essence)
    local maxEssence = UnitPowerMax("player", Enum.PowerType.Essence)
    for i = 1, 6 do
        if i > maxEssence then
            states:Remove(i) -- wipe allstates[6]
        else
            local value = currentEssence >= i and 1 or 0
            local newState = {
                progressType = "static",
                value = value,
                total = 1
            }
            states:Update(i, newState)
        end
    end
    -- no need to return true
end
```

WeakAuras/TSUHelpers.lua

@@ -0,0 +1,91 @@
+if not WeakAuras.IsLibsOK() then return end
+local AddonName, Private = ...
+
+local function fixMissingFields(state)
+  if type(state) ~= "table" then return end
+  -- set show
+  if state.show == nil then
+    state.show = true
+  end
+end
+
+local remove = function(states, key)
+  local changed = false
+  local state = states[key]
+  if state then
+    state.show = false
+    state.changed = true
+    states.__changed = true
+    changed = true
+  end
+  return changed
+end
+
+local removeAll = function(states)
+  local changed = false
+  for _, state in pairs(states) do
+    state.show = false
+    state.changed = true
+    changed = true
+  end
+  if changed then
+    states.__changed = true
+  end
+  return changed
+end
+
+local function recurseUpdate(t1, t2)
+  local changed = false
+  for k, v in pairs(t2) do
+    if type(v) == "table" and type(t1[k]) == "table" then
+      if recurseUpdate(t1[k], v) then
+        changed = true
+      end
+    else
+      if t1[k] ~= v then
+        t1[k] = v
+        changed = true
+      end
+    end
+  end
+  return changed
+end
+
+local update = function(states, key, newState)
+  local changed = false
+  local state = states[key]
+  if state then
+    fixMissingFields(newState)
+    changed = recurseUpdate(state, newState)
+    if changed then
+      state.changed = true
+      states.__changed = true
+    end
+  end
+  return changed
+end
+
+local create = function(states, key, newState)
+  states[key] = newState
+  states[key].changed = true
+  states.__changed = true
+  fixMissingFields(states[key])
+  return true
+end
+
+local createOrUpdate = function(states, key, newState)
+  key = key or ""
+  if states[key] then
+    return update(states, key, newState)
+  else
+    return create(states, key, newState)
+  end
+end
+
+Private.allstatesMetatable = {
+  __index = {
+    Update = createOrUpdate,
+    Remove = remove,
+    RemoveAll = removeAll
+  }
+}