Module string

String shape types and operations.

Defines the shape describing the textual values a resource may carry and its constraint types, and provides the factories stating them, mapping the JSON string type to XSD 1.0 string and temporal datatypes. The string factory bounds a shape by length, lexical and enumeration constraints; the format factories fix the datatype and lexical pattern of a particular format.

¹ XSD 1.0 datatypes are referenced by RDF 1.1 and JSON-LD 1.1 as normative

² XSD 1.1 Part 2 § D.3.4 permits optional timezone indicators for gYear as a deviation from ISO 8601

³ Requires exactly 3 fractional second digits (millisecond precision) and UTC timezone (Z only); typed as xsd:dateTime rather than the more specific xsd:dateTimeStamp for compatibility with SPARQL temporal functions, which are defined over xsd:dateTime

Compatibility

Defining string shapes

import { string } from '@metreeca/blue/string';

const value = string();                                     // unconstrained string
const name = string({ minLength: 1, maxLength: 100 });      // length-constrained
const code = string({ pattern: /^[A-Z]{3}-\d{4}$/ });       // pattern-constrained
const status = string({ in: ["active", "inactive"] });      // enumeration-constrained
const state = string("open", "closed");                     // the same, stated as bare values
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Specialised string factories

Predefined factories for common string formats:

import {
  text, markdown, email, phone, iri, url, tag, date, time, instant, timestamp, duration
} from '@metreeca/blue/string';

const label = text();         // single-line plain text
const body = markdown();      // Markdown formatted text
const contact = email();      // RFC 5321 email address
const mobile = phone();       // ITU-T E.164 telephone number
const identifier = iri();     // RFC 3987 IRI reference
const link = url();           // RFC 3986 hierarchical URL
const language = tag();       // BCP 47 language tag
const birthday = date();      // ISO 8601 date (YYYY-MM-DD)
const start = time();         // ISO 8601 time (hh:mm:ss)
const created = instant();    // ISO 8601 datetime
const modified = timestamp(); // ISO 8601 timestamp (millisecond precision, UTC)
const validity = duration();  // ISO 8601 duration
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Using in resource shapes

import { multiple, optional, required, resource } from '@metreeca/blue/resource';
import { date, email, string } from '@metreeca/blue/string';

const Person = resource({
  name: required(string({ minLength: 1 })),
  email: optional(email()),
  birthDate: optional(date())
});
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