spekvet

spekvet

Spekvet is a backend-focused JavaScript validator with a compact, composable API. Its single small module suits serverless functions while supporting arbitrary executable schemas, including recursive ones. It keeps validation strict and transparent: schemas validate rather than transform, and callers control coercion and security limits.

Features

• One small, dependency-free module with no compilation
• Strict validation without coercion
• Synchronous predicates and fail-fast behavior
• Composable executable schemas
• Machine-readable .diff() results and throwing .assert() checks

Example

import { spec } from 'spekvet';

const user = spec({
  name: spec.string,
  age: spec.number.min(0),
});

user.diff({ name: 42, age: 20 });
// { kind: 'type', expected: 'string', input: 42, path: ['name'] }

user.assert({ name: 'Ada', age: 36 });
// Returns the input unchanged.

See the walkthrough for the complete API, recursive validation, error shapes, and practical recipes.