zod example

index.ts

import { z } from "zod"

// USER

const userNameSchema = z
	.string({
		invalid_type_error: "Username must be a string",
		required_error: "Username is required",
	})
	.min(2, { message: "Username must be at least 2 characters long" })
	.refine((name) => !name.includes(" "), {
		message: "Username must not contain spaces",
	})
	.refine((name) => name != "admin", { message: "Username cannot be admin" })

const passwordSchema = z
	.string({
		required_error: "Password is required",
	})
	.min(6, { message: "Password must be at least 6 characters long" })
	.regex(/\d/, { message: "Password must contain at least one digit" })
	.regex(/[a-zA-Z]/, { message: "Password must contain at least one letter" })
	.regex(/[!@#$%^&*(),.?":{}|<>]/, {
		message: "Password needs to have at least one special character.",
	})

const addressSchema = z.object({
	street: z.string().nonempty(),
	city: z.string().nonempty(),
	zip: z.union([z.string(), z.number()]).transform((val) => String(val)),
})

const userSchema = z.object({
	username: userNameSchema,
	password: passwordSchema,
	email: z.string().email(),
	newsletter: z.boolean().default(false),
	plan: z.enum(["free", "pro", "premium"]).default("free"),
	age: z.number().min(0).max(200).optional(),
	interests: z.array(z.string().nonempty()).max(100).default([]),
	website: z
		.string()
		.url({
			message: "Website must be a valid URL",
		})
		.optional(),
	address: addressSchema.optional(),
})

type User = z.infer<typeof userSchema>

const validUser = {
	username: "john_doe",
	password: "01a224@123",
	email: "[email protected]",
	interests: ["coding", "cycling"],
	address: {
		street: "123 Main St",
		city: "Springfield",
		zip: 12345,
	},
}

const { data, error } = userSchema.safeParse(validUser)

if (error) {
	error.errors.forEach((e) => {
		console.info(e.message)
	})
} else {
	console.info(data)
}

// TODOS

const TodoSchema = z.object({
	id: z.string().nonempty(),
	text: z.string().nonempty(),
	done: z.boolean().default(false),
})

const TodosSchema = z.array(TodoSchema)

type Todo = z.infer<typeof TodoSchema>

const localStorageMock = {
	getItem: (key: string) =>
		key === "todos" ? `[{"id":"123","text":"fix code","done":false}]` : null,
}

function get_todos(): Todo[] {
	let todos: unknown = undefined
	try {
		const todos_string = localStorageMock.getItem("todos")
		if (!todos_string) return []
		todos = JSON.parse(todos_string)
	} catch {
		console.error("Invalid JSON data")
	}

	const { data, success } = TodosSchema.safeParse(todos)

	if (!success) {
		console.error("Invalid todos")
		return []
	}

	return data
}

const todos = get_todos()
console.info(todos)