Zod DeepRequired

deep_required.test.ts

import { describe, expect, it } from 'vitest';
import { z } from 'zod';
import { deepRequired } from './zod_util.js';

describe('deepRequired', () => {
  it('makes all fields in a flat object required', () => {
    const schema = z.object({
      required: z.string(),
      optional: z.string().optional(),
      nullable: z.string().nullable(),
      optionalAndNullable: z.string().optional().nullable(),
    });

    const required = deepRequired(schema);

    // All fields should be required and non-nullable
    type Schema = z.infer<typeof required>;
    const shouldBeRequired: Schema = {
      required: 'test',
      optional: 'test',
      nullable: 'test',
      optionalAndNullable: 'test',
    };

    // @ts-expect-error - missing properties should error
    const shouldError: Schema = {
      required: 'test',
    };

    // Test runtime validation
    expect(() =>
      required.parse({
        required: 'test',
        optional: 'test',
        nullable: 'test',
        optionalAndNullable: 'test',
      })
    ).not.toThrow();

    // Should throw when missing properties
    expect(() =>
      required.parse({
        required: 'test',
      })
    ).toThrow();
  });

  it('makes nested object fields required', () => {
    const schema = z.object({
      nested: z
        .object({
          required: z.string(),
          optional: z.string().optional(),
        })
        .optional(),
    });

    const required = deepRequired(schema);

    // All fields should be required and non-nullable
    type Schema = z.infer<typeof required>;
    const shouldBeRequired: Schema = {
      nested: {
        required: 'test',
        optional: 'test',
      },
    };

    const shouldError: Schema = {
      // @ts-expect-error - missing properties should error
      nested: {
        required: 'test',
      },
    };

    // Test runtime validation
    expect(() =>
      required.parse({
        nested: {
          required: 'test',
          optional: 'test',
        },
      })
    ).not.toThrow();

    // Should throw when missing properties
    expect(() =>
      required.parse({
        nested: {
          required: 'test',
        },
      })
    ).toThrow();
  });

  it('makes array elements required', () => {
    const schema = z.object({
      array: z.array(
        z.object({
          required: z.string(),
          optional: z.string().optional(),
        })
      ),
    });

    const required = deepRequired(schema);

    // Test runtime validation
    expect(() =>
      required.parse({
        array: [
          {
            required: 'test',
            optional: 'test',
          },
        ],
      })
    ).not.toThrow();

    // Should throw when missing properties in array elements
    expect(() =>
      required.parse({
        array: [
          {
            required: 'test',
          },
        ],
      })
    ).toThrow();
  });

  it('makes tuple elements required', () => {
    const schema = z.object({
      tuple: z.tuple([z.string(), z.number().optional(), z.boolean().nullable()]),
    });

    const required = deepRequired(schema);

    // Test runtime validation
    expect(() =>
      required.parse({
        tuple: ['test', 42, true],
      })
    ).not.toThrow();

    // Should throw when missing tuple elements
    expect(() =>
      required.parse({
        tuple: ['test'],
      })
    ).toThrow();
  });

  it('preserves non-optional/nullable schemas', () => {
    const schema = z.object({
      string: z.string(),
      number: z.number(),
      boolean: z.boolean(),
      literal: z.literal('test'),
      enum: z.enum(['a', 'b', 'c']),
    });

    const required = deepRequired(schema);

    // Test that the schemas are unchanged
    expect(() =>
      required.parse({
        string: 'test',
        number: 42,
        boolean: true,
        literal: 'test',
        enum: 'a',
      })
    ).not.toThrow();

    // Should still throw for invalid values
    expect(() =>
      required.parse({
        string: 42,
        number: 'test',
        boolean: 'true',
        literal: 'wrong',
        enum: 'd',
      })
    ).toThrow();
  });
});

deep_required.ts

import {
  ZodTypeAny,
  ZodObject,
  ZodOptional,
  ZodArray,
  ZodNullable,
  ZodTuple,
  ZodRawShape,
  ZodTupleItems,
} from 'zod';

export type DeepRequired<T extends ZodTypeAny> =
  T extends ZodObject<ZodRawShape>
    ? ZodObject<
        { [k in keyof T['shape']]: DeepRequired<T['shape'][k]> },
        T['_def']['unknownKeys'],
        T['_def']['catchall']
      >
    : T extends ZodArray<infer Type, infer Card>
      ? ZodArray<DeepRequired<Type>, Card>
      : T extends ZodOptional<infer Type>
        ? DeepRequired<Type>
        : T extends ZodNullable<infer Type>
          ? DeepRequired<Type>
          : T extends ZodTuple<infer Items>
            ? {
                [k in keyof Items]: Items[k] extends ZodTypeAny ? DeepRequired<Items[k]> : never;
              } extends infer PI
              ? PI extends ZodTupleItems
                ? ZodTuple<PI>
                : never
              : never
            : T;

function deepRequiredInternal(schema: ZodTypeAny): any {
  if (schema instanceof ZodObject) {
    const newShape: any = {};

    for (const key in schema.shape) {
      const fieldSchema = schema.shape[key];
      newShape[key] = deepRequiredInternal(fieldSchema);
    }
    return new ZodObject({
      ...schema._def,
      shape: () => newShape,
    }) as any;
  } else if (schema instanceof ZodArray) {
    return new ZodArray({
      ...schema._def,
      type: deepRequiredInternal(schema.element),
    });
  } else if (schema instanceof ZodOptional) {
    return deepRequiredInternal(schema.unwrap());
  } else if (schema instanceof ZodNullable) {
    return deepRequiredInternal(schema.unwrap());
  } else if (schema instanceof ZodTuple) {
    return ZodTuple.create(schema.items.map((item: any) => deepRequiredInternal(item)));
  } else {
    return schema;
  }
}

export function deepRequired<T extends ZodTypeAny>(schema: T): DeepRequired<T> {
  return deepRequiredInternal(schema) as DeepRequired<T>;
}

LICENSE

These files are licensed under the MIT license, as with the Zod project.

Copyright 2024 Daniel Imfeld, Colin McDonnell

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.