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zod-schemas

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Zod schema validation patterns for API types

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Zod Schema Validation

Define types in state-manager/types.ts using Zod schemas for runtime validation.

Structure

  • Define Zod schemas first, then infer TypeScript types
  • Use enums for tag types
  • Export both schemas and inferred types
// ✅ GOOD - state-manager/types.ts
import { z } from "zod";

// 1. Define tag types as enum
export enum MyDataTags {
  Items = "Items",
  Item = "Item",
}

// 2. Define Zod schemas with validation rules
const ItemSchema = z.object({
  id: z.string().uuid(),
  name: z.string().min(1),
  value: z.number().min(0),
  status: z.enum(["active", "inactive"]),
  createdAt: z.string().datetime(),
});

const ItemResponseSchema = z.object({
  data: ItemSchema,
  meta: z.object({
    timestamp: z.string(),
    version: z.string(),
  }),
});

const ItemListResponseSchema = z.object({
  items: z.array(ItemSchema),
  pagination: z.object({
    nextCursor: z.string().optional(),
    total: z.number(),
  }),
});

// 3. Infer TypeScript types from schemas
export type Item = z.infer<typeof ItemSchema>;
export type ItemResponse = z.infer<typeof ItemResponseSchema>;
export type ItemListResponse = z.infer<typeof ItemListResponseSchema>;

// 4. Define query params as interfaces
export interface GetItemsParams {
  search?: string;
  limit?: number;
  cursor?: string;
}

// 5. Export schemas for runtime validation
export { ItemSchema, ItemResponseSchema, ItemListResponseSchema };

Using Schemas in API

// state-manager/api.ts
import { ItemListResponseSchema, type ItemListResponse } from "./types";

endpoints: (build) => ({
  getItems: build.query<ItemListResponse, GetItemsParams>({
    query: (params) => ({ url: "items", params }),
    transformResponse: (response: unknown) => {
      // Runtime validation
      return ItemListResponseSchema.parse(response);
    },
  }),
}),

Best Practices

  • Use .min(), .max(), .uuid(), .email() for field validation
  • Use z.enum() for fixed string values
  • Use z.union() for multiple possible types
  • Use .optional() for nullable fields
  • Always infer types with z.infer<typeof Schema>