API reference › @evolu/common › Type › Email

const Email: brand(
  "Email",
  String,
  (value: string) =>
    /^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$/u.test(
      value,
    )
      ? ok()
      : err<EmailError>({ type: "Email", value }),
  formatEmailError,
);

Defined in: packages/common/src/Type.ts:9164

Email address as defined by the WHATWG HTML Standard.

Email accepts a valid email address, the syntax browsers enforce for <input type="email">. The HTML Standard deliberately departs from RFC 5322: it rejects quoted local parts, comments, IP address literals, and whitespace, and it accepts only ASCII. Use the ASCII (xn--) form of internationalized domains.

Email does not normalize. The local part is case-sensitive, so different Email strings can still reach the same mailbox, and only a delivered message proves that an address exists.

The HTML Standard limits each domain label to 63 characters but sets no total length. SMTP limits an address to 254 characters; compose maxLength(254)(Email) when that limit matters.

Example

import {
  assertEqual,
  assertErr,
  assertOk,
  Email,
  maxLength,
} from "@evolu/common";

assertOk(Email.fromUnknown("ada@example.com"), "ada@example.com");
assertOk(Email.fromUnknown("Ada@Example.com"), "Ada@Example.com");

const invalid = Email.fromUnknown("Ada <ada@example.com>");
assertErr(invalid);
assertEqual(invalid.error, {
  type: "Email",
  value: "Ada <ada@example.com>",
});

const SmtpEmail = maxLength(254)(Email);
assertErr(SmtpEmail.fromUnknown(`${"a".repeat(251)}@b.c`));
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