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Is phone

isPhone validates that a value is a loosely formatted phone number.

It provides a flexible, user‑friendly check suitable for general input fields: the value must be a string, and after removing all non‑digit characters, at least seven digits must remain. Any non‑string value or digit‑stripped string shorter than seven digits results in a single validation event. Otherwise, it produces no validation output.

Signature

Through the API:

.isPhone();

And internally:

export const isPhone: ValidationRule
(value: unknown, path: FieldPath) => Promise<ReadonlyArray<JaneEvent>>

Events

Event code Description
type.not.valid Value is not a string.
string.not.phone String does not contain at least seven digits.

Design rationale

  • Provides a permissive, user‑friendly phone validator appropriate for common form fields.
  • Rejects non‑string values early with a structural‑type diagnostic.
  • Strips non‑digit characters to accommodate formatting variations ((555) 123‑4567, 555‑1234, etc.).
  • Enforces a minimal digit count (7) to avoid obviously invalid numbers.
  • Emits exactly one event per failure for clarity and composability.
  • Pure, total, async‑compatible, and returns a readonly array of JaneEvent objects.
  • Preserves the provided path and supports pipeline‑level userMessage overrides.

Invoke

isPhone runs only when explicitly included in a boundary or pipeline. It does not run automatically.

The rule activates when:

  • The value is any JavaScript value.
  • If the value is not a string, emits type.not.valid.
  • If the digit‑stripped string has fewer than seven digits, emits string.not.phone.
  • Otherwise, returns an empty result set.

Examples

Valid — loosely formatted phone numbers

await isPhone("(555) 123‑4567", "$");
// → []

await isPhone("555‑1234", "$");
// → []

Invalid — non‑string values

await isPhone(1234567, "$");
// → [
//     JaneEvent{
//       kind: "error",
//       code: "type.not.valid",
//       path: "$",
//       ...
//     }
//   ]

Invalid — insufficient digits

await isPhone("123‑45", "$");
// → [
//     JaneEvent{
//       kind: "error",
//       code: "string.not.phone",
//       path: "$",
//       ...
//     }
//   ]