Validators

Built-in validation rules for use with useForm and useField. All accept an optional custom error message.

import {
  required, minLength, maxLength,
  pattern, min, max, email, url, custom
} from "@allem-sdk/forms";

Available validators

Validator	Signature	Description
required	required(msg?)	Field must not be empty
minLength	minLength(n, msg?)	Minimum string length
maxLength	maxLength(n, msg?)	Maximum string length
min	min(n, msg?)	Minimum numeric value
max	max(n, msg?)	Maximum numeric value
pattern	pattern(regex, msg?)	Must match regex
email	email(msg?)	Valid email format
url	url(msg?)	Valid URL (http/https)
custom	custom(fn)	Custom validation function

Custom validator

const passwordStrength = custom<string>((value) => {
  if (value.length < 8) return "Must be at least 8 characters";
  if (!/[A-Z]/.test(value)) return "Must contain an uppercase letter";
  if (!/[0-9]/.test(value)) return "Must contain a number";
  return undefined; // valid
});

const form = useForm({
  password: {
    initialValue: "",
    rules: [required(), passwordStrength],
  },
});