How to make a function run when something is added to an Array or removed

[Myron_RDS (Myron)]

I want a function to run when something is removed or added to a table (array)
This metamethod won’t make it work so is there anyway to make it work?

local PetsMT = {
    __newindex = function()
        print("META TABLE ADDED TO")
    end,
}

local Pets = setmetatable({}, PetsMT)
table.insert(Pets, "Cat")

Expected Output: “META TABLE ADDED TO”
Output: Nothing

So I want to fire client every time Pets is added to

but the print won’t run

[PuffoThePufferfish (Puffo)]

(I don’t know metatables that well)
Instead of using table.insert, just set the first index of the table to “Cat”

Pets[1] = "Cat"

[Myron_RDS (Myron)]

it’s not gonna be the first index. the index just depends on how manyh there already are in the array
I guess Pets[#Pets + 1] = “Cat” could work?

[PuffoThePufferfish (Puffo)]

then whatever index you want (30char)
yea