Detects changes within a table using a metatable with function callbacks for .Removed, .Added, .Changed

Table changed.luau

--[[ 
Created by @depso (depthso)
  
Example usage:

local Table = Module.new({
  HiBlud = 67
}, {
    Changed = function(...)
      print("Changed", ...)
    end,
    Removed = function(...)
      print("Removed", ...)
    end,
    Added = function(...)
      print("Added", ...)
    end,
})

--// Test data
Table.HiBlud = 41
Table.Gay = "Burner"
Table.HiBlud = nil
]]

type Table = {any}|{[any]: any}
type Callbacks = {
    Removed: ((Key: any) -> nil)?,
    Added: ((Key: any, Value: any) -> nil)?,
    Changed: ((Key: any, Value: any, Previous: any) -> nil)?,
}

local Module = {
    Removed = nil,
    Added = nil,
    Changed = nil
}

function Module.new(Table: Table, Callbacks: Callbacks)
    --// Callbacks
    local Removed = Callbacks.Removed
    local Changed = Callbacks.Changed
    local Added = Callbacks.Added

    return setmetatable({}, {
        __newindex = function(_, Key, Value)
            local Previous = Table[Key]

            --// Fire callbacks
            if Added and Previous == nil then
                Added(Key, Value)
            elseif Removed and Value == nil then
                Removed(Key)
            elseif Changed and Previous ~= nil and Value ~= nil and Value ~= Previous then
                Changed(Key, Value, Previous)
            end

            Table[Key] = Value
        end,
        __index = Table,
        __len = Table,
        __tostring = Table
    })
end

return Module

67