What is Typed?

CAUTION

Library is still under development; use at your own risk

typed is a runtime type validation library for luau. If you have used Zod before, the api should feel a bit familiar: building schemas to define what a value should look like, then be able to validate it against data that comes from arbitrary sources.

At a First Glance

const t = require("typed")

-- define a user schema
const userSchema = t.table({
	username = t.string({
		length = {
			min = 3,
			max = 20,
		},
	}),
	age = t.number({ min = 18 }),
	email = t.optional(t.string({ match = "^.+@.+%..+$" })),
	tags = t.array(t.string()),
})

-- pull out the generated type using the infer type function
type User = t.infer<typeof(userSchema)>

const rawData = {
	username = "alex",
	age = 25,
	email = "alex@example.com",
	tags = { "admin", "developer" },
}

-- attempt to validate and parse the raw data using the created schema
const result = userSchema.parse(rawData)

if result.ok then
	const user: User = result.value
	print(user)
else
	print("failed to validate:", t.formatIssues(result.issues))
end

If rawData is missing username, or age is 17, or email doesn't look like an email, result.ok is false and result.issues would tell you exactly what failed instead of letting a bad value get dropped with no information, or even worse, having the bad value slip through into the rest of your program.

At the Core

typed is made of small set of composable parts.

• Base schemas - t.any, t.unknown, t.never, t.literal, t.is
• Builtins - t.boolean, t.number, t.string, t.none, t.vector, t.buffer, t.callable, t.userdata
• Structures - t.table, t.array, t.iterable
• Modifiers - t.optional, t.transform
• Combinators - t.union, t.intersect

Every single schema -- no matter how it was created -- contains the same set of methods you can call: validate, parse, unwrapParse, and enforce.

Next Steps

• Getting Started - Installing typed into your project, and learn how to build your first schema
• Guide - Get into the intricacies of typed