How to use the rdf-ext.createStore function in rdf-ext

var blogGraph = rdf.createGraph([
  rdf.createTriple(
    rdf.createNamedNode(blogIri),
    rdf.createNamedNode('http://schema.org/name'),
    rdf.createLiteral('simple blog')),
  rdf.createTriple(
    rdf.createNamedNode(blogIri),
    rdf.createNamedNode('http://schema.org/post'),
    blogPostNode),
  rdf.createTriple(
    blogPostNode,
    rdf.createNamedNode('http://schema.org/headline'),
    rdf.createLiteral('first blog post'))
])

var blogStore = rdf.createStore()

blogStore.add('http://example.org/blog', blogGraph).then(function () {
  return simple(blogContext, blogIri, null, blogStore).get()
}).then(function (blog) {
  console.log('fetched blog from: ' + blog._iri.toString())
  console.log(blog.name)
  console.log(blog.post.shift().headline)

  // move blog to new location
  blog.iri('http://example.org/new-blog')

  return blog.save()
}).then(function (blog) {
  console.log('stored blog at: ' + blog._iri.toString())

  return blogStore.graph('http://example.org/new-blog')

constructor(options: RDFStoreOptions) {
        this.parser = options.parser;
        this.acceptBlankNodes = Boolean(options.acceptBlankNodes);

        this.rdfStorage = createStore();
        this.prefs = {
            RDF: prefixFactory('http://www.w3.org/1999/02/22-rdf-syntax-ns#'),
            RDFS: prefixFactory('http://www.w3.org/2000/01/rdf-schema#'),
            FOAF: prefixFactory('http://xmlns.com/foaf/0.1/'),
            XSD: prefixFactory('http://www.w3.org/2001/XMLSchema#'),
            OWL: prefixFactory('http://www.w3.org/2002/07/owl#'),
        };
    }