function isRelativeURI( value ) {
	var authority;
	var scheme;
	var parts;
	var path;
	if ( !isString( value ) ) {
		return false;
	}
	// Check for illegal characters:
	if ( RE_ILLEGALS.test( value ) ) {
		return false;
	}
	// Check for incomplete HEX escapes:
	if (
		RE_HEX1.test( value ) ||
		RE_HEX2.test( value )
	) {
		return false;
	}
	// Split the string into various URI components:
	parts = value.match( RE_URI );
	scheme = parts[ 1 ];
	authority = parts[ 2 ];
	path = parts[ 3 ];

	if (
		!scheme ||
		!scheme.length ||
		!RE_SCHEME.test( scheme.toLowerCase() )
	) {
		return true;
	}
	if (
		!authority &&
		RE_PATH.test( path )
	) {
		return true;
	}
	return false;
}
Tests whether a value is a relative URI.

@param {*} value - value to test
@returns {boolean} boolean indicating whether a value is a relative URI

@example
var bool = isRelativeURI( './beep/boop' );
// returns true

@example
var bool = isRelativeURI( '/dashboard/admin' );
// returns true

@example
var bool = isRelativeURI( 'https://wikipedia.org' );
// returns false

@example
var bool = isRelativeURI( null );
// returns false