Signal Values

A signal stores a value.

Key Point

Signals are the core component of Reheaven.

When you create a signal, Reheaven gives you two functions:

• a getter for reading the value
• a setter for updating the value

local count, setCount = Reheaven.signal(0)

Reading a Signal

Call the getter to read the current value:

print(count()) -- 0

Setting a Signal

Call the setter to replace the value:

setCount(10)

print(count()) -- 10

Updating From the Previous Value

The setter can also receive a function.

This is useful when the next value depends on the current value:

setCount(function(current)
    return current + 1
end)

print(count()) -- 11

Updater functions are also a clean way to update a signal from inside an effect.

Reheaven.effect(function()
    setCount(function(current)
        return current + 1
    end)
end)

Reheaven also protects against same-effect self-write recursion:

Reheaven.effect(function()
    setCount(count() + 1)
end)

When this happens, Reheaven skips rerunning the same effect and shows a debug warning.

Same Values

If a signal is set to the same value, Reheaven skips the update.

setCount(11)
setCount(11)

This helps avoid unnecessary watcher, effect, and computed updates.

Table State

Signals can store tables too:

local player, setPlayer = Reheaven.signal({
    coins = 100;
    level = 1;
})

Update table state by replacing the table. The recommended way is to use a functional update:

setPlayer(function(current)
    return {
        coins = current.coins + 50;
        level = current.level;
    }
end)

You can also read the current value first and then set a new table:

local currentPlayer = player()

setPlayer({
    coins = currentPlayer.coins + 50;
    level = currentPlayer.level;
})

Prefer functional updates when the next value depends on the previous value.

Then read it normally:

print(player().coins) -- 150

Next Steps

Next, learn how computed values derive new state from signals.