debug.setupvalue Synchronous

Replace one value captured by a Luau closure. This lets you change a closure’s state without rebuilding it.

Syntax

Luau

debug.setupvalue(target: Function | number, index: number, value: any) -> ()

Parameters

Function parameters
Parameter	Type	Description
`target`	`Function \| number`	A Luau function or visible stack level.
`index`	`number`	One-based upvalue slot.
`value`	`any`	New captured value.

()

No value.

Luau

local message = "before"
local function readMessage() return message end
debug.setupvalue(readMessage, 1, "after")
print(readMessage()) -- after