zod-non-empty-array

Make zod compatible with fp-ts non-empty constructs.

Installation

npm install zod-non-empty-array

Requirements

• Node.js v.16+

Quick start

import { z as zod } from 'zod';
import { identity } from 'fp-ts/lib/function';
import * as NonEmptyArray from 'fp-ts/NonEmptyArray';
import { transformNonEmptyArray } from 'zod-non-empty-array';

// create zod schema
const schema = zod.object({
  id: zod.number().int().positive(),
  title: zod.string(),
  authors: zod
    .array(zod.string())
    // must have at least one author
    .transform(transformNonEmptyArray),
});

type Article = zod.infer<typeof schema>;

// parse some invalid value
const article = schema.parse({
  id: 1,
  title: 'A case-study of the use of fp-ts in a real-world project',
  authors: ['John Doe', 'Jane Doe'],
});

// article.authors is now compatible with fp-ts
const principalAuthor = pipe(article.authors, NonEmptyArray.head);

Motivation

Zod already supports non-empty array validation. However, the generated type is incompatible with fp-ts.

Specifically, fp-ts defines NonEmptyArray as follows...

interface NonEmptyArray<T> extends Array<T> {
  0: T;
}

While, zod defines NonEmptyArray as follows...

type ZodNonEmptyArray<T> = [T, ...T[]];

This incompatibility makes it difficult to integrate zod with fp-ts.

The zod-non-empty-array library addresses the incompatibility issue by exposing zod transformers that return fp-ts constructs. Instead of zod.array(...).nonempty() use zod.array(...).transform(transformNonEmptyArray).

API

• transformNonEmptyArray
• transformReadonlyNonEmptyArray

Contribute

Source code contributions are most welcome. Please open a PR, ensure the linter is satisfied and all tests pass.

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License

MIT