The absolute base identifier to resolve against
The reference to resolve
The resolved absolute identifier
While RFC 3986 § 5 defines a path-merging algorithm that technically applies to all URI schemes, opaque identifiers lack the hierarchical path such merging operates on, leaving relative resolution semantically undefined: a relative reference against an opaque base is rejected outright, rather than resolved to an identifier its scheme gives no meaning to.
RangeError If base is not a valid absolute identifier or reference is not a valid
relative reference, for instance because it carries an isolated UTF-16 surrogate or opens with //
RangeError If a relative reference cannot be resolved against an opaque base
Resolves a reference against a base identifier.
baseandreferenceto produce an absolute identifierurn:,mailto:): Absolute references are returned unchanged; relative references cannot be resolved and throw an errorResolution never escapes the root of
base:..segments climbing above it are clipped as prescribed by the RFC 3986 § 5.4.2 abnormal examples, so the resolved identifier always carries the scheme and authority ofbase.