zod/src/v3/helpers/partialUtil.ts

TypeScript-first schema declaration and validation library with static type inference

import type {
  ZodArray,
  ZodNullable,
  ZodObject,
  ZodOptional,
  ZodRawShape,
  ZodTuple,
  ZodTupleItems,
  ZodTypeAny,
} from "../types.js";

export namespace partialUtil {
  export type DeepPartial<T extends ZodTypeAny> = T extends ZodObject<ZodRawShape>
    ? ZodObject<
        { [k in keyof T["shape"]]: ZodOptional<DeepPartial<T["shape"][k]>> },
        T["_def"]["unknownKeys"],
        T["_def"]["catchall"]
      >
    : T extends ZodArray<infer Type, infer Card>
      ? ZodArray<DeepPartial<Type>, Card>
      : T extends ZodOptional<infer Type>
        ? ZodOptional<DeepPartial<Type>>
        : T extends ZodNullable<infer Type>
          ? ZodNullable<DeepPartial<Type>>
          : T extends ZodTuple<infer Items>
            ? {
                [k in keyof Items]: Items[k] extends ZodTypeAny ? DeepPartial<Items[k]> : never;
              } extends infer PI
              ? PI extends ZodTupleItems
                ? ZodTuple<PI>
                : never
              : never
            : T;
}