validify

A lightweight, type-safe validation and schema library for JavaScript and TypeScript. Built for form validation, API input validation, and runtime type checking with full TypeScript inference.

📖 Full documentation (فارسی): docs/DOCUMENTATION.md — API reference

Installation

npm install validify

Features

• Type-safe – Full TypeScript support with automatic type inference
• Lightweight – Zero dependencies, tree-shakeable API
• i18n-ready – Error codes suitable for localization
• Composable – Build complex schemas from simple ones
• Flexible – Use parse() to throw, or safeParse() for controlled handling

Quick Start

import { string, number, object, optional } from 'validify';

const userSchema = object({
  name: string({ minLength: 1, maxLength: 100 }),
  email: string({ email: true }),
  age: optional(number({ min: 0, max: 150 })),
});

// Parse (throws on failure)
const user = userSchema.parse({ name: 'Alice', email: '[email protected]' });
// user: { name: string; email: string; age: number | undefined }

// Safe parse (returns result object)
const result = userSchema.safeParse(input);
if (result.success) {
  console.log(result.data);
} else {
  console.error(result.issues);
}

Schema Types

string

string({ minLength?: number, maxLength?: number, pattern?: RegExp, email?: boolean, url?: boolean, trim?: boolean })

number

number({ min?: number, max?: number, integer?: boolean })

boolean

boolean()

array

array({ minLength?: number, maxLength?: number, itemSchema?: Schema<T> })

object

object({ key: schema, ... })

optional

Wraps any schema to allow undefined or null:

object({
  name: string(),
  nickname: optional(string()),
})

enum

enumSchema(['a', 'b', 'c'] as const)

Error Handling

import { ValidationError } from 'validify';

try {
  schema.parse(data);
} catch (err) {
  if (err instanceof ValidationError) {
    // All validation issues
    console.log(err.issues);

    // For form fields: { fieldPath: message }
    const fieldErrors = err.toFieldMap();

    // For i18n: [{ code, path, value }]
    const report = err.toReport();
  }
}

Composing Schemas

import { compose, string } from 'validify';

const trimmedEmail = compose(
  string({ trim: true }),
  string({ email: true })
);

Merging Object Shapes

import { merge, object, string, number } from 'validify';

const baseShape = { id: number() };
const userShape = { name: string(), email: string({ email: true }) };
const schema = merge(baseShape, userShape);

i18n

Error codes are exposed for mapping to localized messages:

import { ErrorCodes } from 'validify';

// ErrorCodes: invalid_type, string_too_short, string_email, number_too_small, ...

License

MIT © Alireza Aminzadeh