How do you give a sub-table a type in Luau?

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#1

Hello! Another question about Luau! there should be more documentation
This time, I’m having problems giving a sub-table a type. It is a table with UDim2 values for tweening.

local positions: any = {
	
	starting = {
		
		chooseLabel = UDim2.new(0.18, 0,0.081, 0),
		drift = UDim2.new(0.07, 0, 0.497, 0),
		rally = UDim2.new(0.07, 0, 0.331, 0)
		
	},
	...
}

I tried writing starting: any = { like the main table but it gives me this error:
image
What does that mean? How can I fix it?

1 Like
#2

If you’re just going to annotate every variable with any that kind of defeats the purpose of type checking. You aren’t using the annotations for its benefits, so just remove the annotations.

#3

I saw in a post that a type for tables still doesn’t exist. I’m using type annotations for the rest though.image

#4

A generic table type doesn’t exist, no. You don’t need to overuse type annotations; for the rest let type inference do it for you. Creating table types just for the sake of creating them to annotate your variables is also a huge waste of time.

Something like

local n: number = 2

is redundant since Luau already knows that 2 is a number. Type annotations are mostly useful for function parameters.

2 Likes
#5

That means there is no specific reason to give the sub-tables a type? Even if I don’t do it, I’d still like to know how to do that.

#6

You need to define type “table” yourself, this is highlighted in the luau documentation. Example:

local positions: {[any]: any} = {}

-- alternatively

type Table = {[any]: any}
local positions: Table = {}

You can also exclusively define an Array/Dictionary type:

type Dictionary = {[string]: any}
type Array = {[number]: any}
2 Likes
#7

Still gives me the error, or did I do something wrong?

#8

starting isn’t a variable.

local positions: { starting: { chooseLabel: UDim2, draft: UDim2, rally: UDim2 } } = {
	starting = {
		chooseLabel = UDim2.new(0.5, 0, 0.5, 0),
		draft = UDim2.new(1, 0, 1, 0),
		rally = UDim2.new(0, 400, 0, 400)
		-- just some example values
	}
}

This would work, however see how much of a waste of time this is?

2 Likes
#9

Yup, I see. Anyway, thank you!