add: simple validation and sanitizing

src/lib/server/validation.ts

@@ -0,0 +1,86 @@
+export function sanitizeString(input: string | null | undefined, maxLength: number = 1000): string | null {
+	if (input === null || input === undefined) {
+		return null;
+	}
+	const trimmed = input.trim();
+	if (trimmed.length > maxLength) {
+		throw new Error(`Input exceeds maximum length of ${maxLength}`);
+	}
+	return trimmed;
+}
+
+export function sanitizeUrl(url: string | null | undefined): string | null {
+	if (!url) {
+		return null;
+	}
+	return url.trim();
+}
+
+export function sanitizeText(input: string | null | undefined, maxLength: number = 10000): string | null {
+	if (input === null || input === undefined) {
+		return null;
+	}
+	const trimmed = input.trim();
+	if (trimmed.length > maxLength) {
+		throw new Error(`Text exceeds maximum length of ${maxLength}`);
+	}
+	return trimmed;
+}
+
+export function sanitizePrice(price: string | null | undefined): number | null {
+	if (!price) {
+		return null;
+	}
+	const parsed = parseFloat(price.trim());
+	if (isNaN(parsed)) {
+		throw new Error('Invalid price format');
+	}
+	if (parsed < 0) {
+		throw new Error('Price cannot be negative');
+	}
+	return parsed;
+}
+
+export function sanitizeColor(color: string | null | undefined): string | null {
+	if (!color) {
+		return null;
+	}
+	return color.trim();
+}
+
+export function sanitizeCurrency(currency: string | null | undefined): string {
+	if (!currency) {
+		return 'DKK';
+	}
+	return currency.trim().toUpperCase();
+}
+
+export function sanitizeUsername(username: string): string {
+	const trimmed = username.trim().toLowerCase();
+	if (trimmed.length < 3 || trimmed.length > 50) {
+		throw new Error('Username must be between 3 and 50 characters');
+	}
+	return trimmed;
+}
+
+export function sanitizeId(id: string | null | undefined): string {
+	if (!id) {
+		throw new Error('ID is required');
+	}
+	const trimmed = id.trim();
+	if (trimmed.length === 0 || trimmed.length > 100) {
+		throw new Error('Invalid ID');
+	}
+	return trimmed;
+}
+
+export function sanitizeToken(token: string | null | undefined): string {
+	if (!token) {
+		throw new Error('Token is required');
+	}
+	const trimmed = token.trim();
+	if (trimmed.length === 0 || trimmed.length > 100) {
+		throw new Error('Invalid token');
+	}
+	return trimmed;
+}