@llazyemail/validator

Small TypeScript validation helpers extracted from hn_email_template outerTemplate component validation.

Install

npm install @llazyemail/validator

Requires a read:packages token for GitHub Packages. See .npmrc.example.

Usage

import { validateInput, ValidationError, minLength } from '@llazyemail/validator';

try {
  validateInput(
    { title: 'Newsletter', email: 'user@example.com' },
    [
      { field: 'title', errorMessage: 'no title was passed' },
      { field: 'email', errorMessage: 'invalid email', rules: ['required', 'email'] },
      { field: 'title', errorMessage: 'title too short', rules: [minLength(3)] },
    ],
  );
} catch (err) {
  if (err instanceof ValidationError) {
    console.error(err.field, err.message, err.ruleMessage);
  }
}

Built-in rules: required, nonEmptyString, string, email, url.

Length helpers: minLength(n), maxLength(n).

A check defaults to ['required', 'nonEmptyString'] when rules is omitted.

Custom Rule functions are also accepted in the rules array.

Develop

npm install
npm test
npm run typecheck
npm run build

tsup emits ESM + CJS + .d.ts into dist/.