zod-json-patch

Generate type-safe Zod 4 schemas for RFC 6902 JSON Patch operations.

Install

bun add zod-json-patch zod

API

createPatchSchema(schema) returns a Zod schema for patches against schema.

PatchOperations<Schema> provides the inferred patch operation type.

Objects and arrays

import { applyPatch } from "fast-json-patch";
import { z } from "zod";
import { createPatchSchema } from "zod-json-patch";

const objectSchema = z.object({
    name: z.string(),
    tags: z.array(z.string()),
});

const operationsSchema = createPatchSchema(objectSchema);

const operations = operationsSchema.parse([
    { op: "replace", path: "/name", value: "Ada" },
    { op: "remove", path: "/tags/0" },
    { op: "add", path: "/tags/-", value: "science" },
]);

const document = applyPatch({ name: "Grace", tags: ["logic"] }, operations).newDocument;

Null and optional fields

null is a value. undefined represents an optional field, which allows add and remove operations.

const objectSchema = z.object({
    middleName: z.string().nullable(),
    nickname: z.string().optional(),
});

const operationsSchema = createPatchSchema(objectSchema);

const operations = operationsSchema.parse([
    { op: "replace", path: "/middleName", value: null },
    { op: "add", path: "/nickname", value: "Amazing Grace" },
]);

Applying patches

fast-json-patch is recommended for applying validated operations, but you can use any RFC 6902-compatible library.