import { z } from 'zod'; export const StringArraySchema = z.array(z.string()); export function assertIsNumber(val: unknown): asserts val is number { z.number().parse(val); } export function assertIsDefined(val: T): asserts val is NonNullable { if (val === undefined || val === null) throw new Error('Value is nullable.'); } export function assertIsStringArray(val: unknown): asserts val is Array { StringArraySchema.parse(val); }