Hello!
I am trying to make a number formatting system with a highly trusted Format Number library made by someone else. However, when I put in my amount into the function shown below (which is a number) it says: “Type ‘string’ could not be converted to number.”
Code:
Please provide any help possible.
Thanks! 
Can you show the FormatCompact function?
You can force a function to return something (I think) by doing this:
function FormatCompact(variables) : number
end
The function:-
-- Configuration
-- The suffixes for abbreviation in every power of thousands.
local COMPACT_SUFFIX = {
"K", "M", "B", "T"
}
local CACHED_SKELETON_SETTINGS = true
--
local MainAPI = require(script.Parent.Main)
local FormatNumberSimpleAPI = { }
local SKELETON_CACHE = if CACHED_SKELETON_SETTINGS then { } else nil
local COMPACT_SKELETON_CACHE = if CACHED_SKELETON_SETTINGS then { } else nil
function FormatNumberSimpleAPI.Format(value: number, skeleton: string?): string
local success
local formatter = nil
assert(type(value) == "number", "Value provided must be a number")
if skeleton == nil then
skeleton = ""
end
assert(type(skeleton) == "string", "Skeleton provided must be a string")
if CACHED_SKELETON_SETTINGS then
formatter = SKELETON_CACHE[skeleton]
end
if not formatter then
success, formatter =
MainAPI.NumberFormatter.forSkeleton(skeleton)
assert(success, formatter :: string)
if CACHED_SKELETON_SETTINGS then
SKELETON_CACHE[skeleton] = formatter
end
end
return (formatter :: MainAPI.NumberFormatter):Format(value)
end
function FormatNumberSimpleAPI.FormatCompact(value: number, skeleton: string?): string
local success
local formatter = nil
assert(type(value) == "number", "Value provided must be a number")
if skeleton == nil then
skeleton = ""
end
assert(type(skeleton) == "string", "Skeleton provided must be a string")
if CACHED_SKELETON_SETTINGS then
formatter = COMPACT_SKELETON_CACHE[skeleton]
end
if not formatter then
success, formatter =
MainAPI.NumberFormatter.forSkeleton(skeleton)
assert(success, formatter :: string)
formatter = (formatter :: MainAPI.NumberFormatter)
:Notation(MainAPI.Notation.compactWithSuffixThousands(COMPACT_SUFFIX))
if CACHED_SKELETON_SETTINGS then
COMPACT_SKELETON_CACHE[skeleton] = formatter
end
end
assert(#COMPACT_SUFFIX ~= 0, "Please provide the suffix abbreviations for FormatCompact at the top of the Simple ModuleScript")
return formatter:Format(value)
end
return table.freeze(FormatNumberSimpleAPI)
The whole script I meant*
The script with the function*
I think the Luau linter is confused.
Try using a different variable name for the return type. I.e.
local formattedAmount = FormatNumber.FormatCompact(amount)
EDIT: This is not a bug it is working correctly.
Looks to be the issue.
You’re setting amount as a string in your original code posted because the :string makes it a string instead of a number.
(Sorry for the poor wording, if there is any, I’m somewhat new to type checking)
The function is not the first “.Format” function but the “FormatCompact” one.
Both functions posted return a string.
If you rely on that functionality, you can possibly silence these errors by doing
amount = tonumber(FormatNumber.FormatCompact(amount))
I was going to recommend this, but I was unable to find any documentation for the library @kry1068 is using. This looks like one of those formatters that condenses numbers to the nearest unit (ie. 100,000,000 becomes 100m), so this may not work if that’s the case.
So I should just remove the “:string”?
Do you rely on :string being there? I’m not sure how your system works so I didn’t suggest that.
See my latest reply. To verify it, would you mind printing amount on the line before you declare the amount? That would ultimately tell us what’s causing the type mismatch.
I will send you a link to the documentation quickly. Hold on a second.
Before declaring the amount, I printed the amount and it returned ‘nil’.
The issue is the reassignment.
You declare amount as a number, then are telling Luau to set it to the return value of FormatCompact, which is not a number.
Your code will work fine if you do this:
local amountText = FormatNumber.FormatCompact(amount) -- Don't need any type hints here
-- set the text to amountText
So I don’t need to declare amount as a number type. Correct?
You should keep amount being declared as number. You can’t reassign it to a string, you have to make a separate variable for the return of FormatCompact.
local function UpdateCurrency(currency: "Seeds" | "Crystal", amount: number)
local amountText = FormatNumber.FormatCompact(amount)
So I did this earlier but it still would send an error. Not that the string could not be changed to a number but that the value must be a number. It was sending the error from the script which defined the format number function.