@shexjs/util

Utility functions to work with ShExJ schemas

Install

npm install @shexjs/util

Invocation

Using partition(<schema>, [<URL>s]) as an example, an illustrative way to invoke it from the command line uses @shexjs/parser and @shexjs/writer:

node -e 'const base = "http://a.example/"
  const schema = require("@shexjs/parser")
    .construct(base, {v: "http://a.example/vocab#"})
    .parse("<S1> { <p1> .; <p2> @<S2>? } <S2> { <p3> @<S3> } <S3> { <p4> @<S1> } <S4> { <p5> . }")
  const partition = require("@shexjs/util").partition(schema, [base + "S2"])
  new (require("@shexjs/writer"))({ base, simplifyParentheses: true })
    .writeSchema(partition,
      (error, text, prefixes) => {
        if (error)
          throw error;
        console.log(text);
      })'

The result is the partition serialized as ShExC:

BASE <http://a.example/>
<S2> {
  <p3> @<S3>
}
<S3> {
  <p4> @<S1>
}
<S1> {
    <p1> . ;
    <p2> @<S2>?
}

Note that <S2> in the input schema has no references to <S1>:

<S1> {
  <p1> .;
  <p2> @<S2>?
}
<S2> {
  <p3> @<S3>
}
<S3> {
  <p4> @<S1>
}
<S4> {
  <p5> .
}

ShExJtoAS(schema)

Parse a ShExJ schema and add ._prefixes and ._index for efficient processing within shexj.js

AStoShExJ(schema)

Remove ._prefixes and ._index from internal schema structure and add schema["@context"] || "http://www.w3.org/ns/shex.jsonld"

ShExRtoShExJ(schema-like-object)

Internal function for parsing ShExR (the ShExRVisitor it uses is not exported)

canonicalize(schema, trimIRI)

Normalize ShExJ by moving all tripleExpression references to their first expression.

BiDiClosure

construct an object with this api:

• needs: {} - mapping from needer to needie
• neededBy: {} - reverse mapping of needs
• add(needer, needie, negated) - record that needer referenced needied, possibly in a negation

nestShapes(schema, options = {})

See which shape declarations have no coreferences and can be nested inside their sole referrer.

options

• no: don't do anything; just report nestable shapes
• transform: function to change shape labels

getPredicateUsage(schema, untyped = {})

Return which predicates appear in which shapes, what their common type is, and whether they are polymorphic.

getDependencies(schema, ret)

Find which shapes depend on other shapes by inheritance or inclusion.

partition(, [s])

Create subset of a schema with only desired shapes and their dependencies.

absolutizeResults(res, base)

In validation results with some relative URLs in it, re-evaluate all [shape, reference, node, subject, predicate, object] property values against base.

getProofGraph(res, db, dataFactory)

Parse a validation result and call db.addQuad() with each triple involved in validation.

Note, this may call db.addQuad() multiple times with the same triple if that triple appears more than once in the validation results.

isWellDefined(schema)

Verify that schema has all necessary referents and conforms to ShEx's stratified negation rules.

valuesToSchema(values)

Convert the results of validating an instance of ShExR against ShExR.shex into a ShExJ schema.

errsToSimple(val, prefixes?, opts?)

Render a validation failure as indented, human-readable lines. opts.explain picks what to include: the failure's "errors", its "repairs" (the cheapest edits that would have made the node conform), or "both"; opts.lex and opts.base control how terms are written.

executeQuery(query, endpoint, dataFactory)

Synchronously execute a SPARQL query against an endpoint.

executeQueryPromise(query, endpoint, dataFactory)

Asynchronously execute a SPARQL query against an endpoint.

parseSparqlJsonResults (jsonObject)

Parse JSON results to internal RDF term representations.

@shexjs/util is one of the shex.js packages; installing shex pulls in the whole suite, and its README maps them.