title: Identifier JS

description: A RFC3986 / RFC3987 compliant fast parser/validator/resolver/composer for NodeJS and browser.

Overview

A fully RFC 3986/3897 compliant URI/IRI parser, validator, resolver and composer, along with other identifier utilities. This library implements the following IANA registered schemes:

• http defined by RFC9110, Section 4.2.1
• https defined by RFC9110, Section 4.2.2
• ws defined by RFC6455, Section 3
• wss defined by RFC6455, Section 3
• file defined by RFC8089, Section 2

Other schemes that are IANA registered schemes and compliant with the generic URI or IRI syntax are also supported. As for the identifiers that are not IANA registered, but compliant with the generic URI or IRI syntax, the preferred schemes are uri and respectively iri.

Install

Requirements

• regular expression with unicode support, available in modern browsers and NodeJS 18+

npm i identifier-js

API

Exports are documented below.

URI (RFC 3986)

Validation

Validate a URI:

• isUri: (value: string) => boolean

Validate a URI reference (absolute or relative):

• isUriReference: (value: string) => boolean

Validate an absolute URI (must include scheme):

• isAbsoluteUri: (value: string) => boolean

Parsing

Parse a URI into structured components:

• parseUri: (value: string) => IdentifierComponents

Parse a URI reference into structured components:

• parseUriReference: (value: string) => RelativeIdentifierComponents

Parse an absolute URI (must include scheme):

• parseAbsoluteUri: (value: string) => AbsoluteIdentifierComponents

IRI (RFC 3987)

Validation

Validate an IRI:

• isIri: (value: string) => boolean

Validate an IRI reference (absolute or relative):

• isIriReference: (value: string) => boolean

Validate an absolute IRI (must include scheme):

• isAbsoluteIri: (value: string) => boolean

Parsing

Parse an IRI into structured components:

• parseIri: (value: string) => IdentifierComponents

Parse an IRI reference into structured components:

• parseIriReference: (value: string) => RelativeIdentifierComponents

Parse an absolute IRI (must include scheme):

• parseAbsoluteIri: (value: string) => AbsoluteIdentifierComponents

Reference Utilities (URI/IRI)

Normalize a URI or IRI reference:

• normalizeReference: (reference: string) => string

Resolve a reference against a base identifier:

• resolveReference: (reference: string, base: string, strict?: boolean, returnParts?: boolean) => string

Note:

• strict (default: true) enables strict resolution behavior.
• returnParts (default: false) returns structured components instead of a string.

Convert a reference into absolute form:

• toAbsoluteReference: (reference: string) => string

Compute a relative reference from base to target:

• toRelativeReference: (target: string, base: string) => string

UUID

Validate a UUID (any version):

• isUUID: (value: string) => boolean

Validate a UUID version 4:

• isUUIDv4: (value: string) => boolean

Testing

• npm test