How to use the n3.DataFactory.literal function in n3

it('should import a single quad correctly', async function () {
      const store = this.store;
      const quads = [
        factory.quad(
          factory.namedNode('http://ex.com/s'),
          factory.namedNode('http://ex.com/p'),
          factory.literal('o', 'en-gb'),
          factory.namedNode('http://ex.com/g')
        )
      ];
      const source = utils.createArrayStream(quads);
      await utils.waitForEvent(store.import(source), 'end', true);
      const matchedQuads = await utils.streamToArray(store.match());
      should(matchedQuads).have.length(1);
    });

it('should import multiple quads correctly', async function () {
      const store = this.store;
      const quads = [
        factory.quad(
          factory.namedNode('http://ex.com/s0'),
          factory.namedNode('http://ex.com/p0'),
          factory.literal('o0', 'en-gb'),
          factory.namedNode('http://ex.com/g0')
        ),
        factory.quad(
          factory.namedNode('http://ex.com/s1'),
          factory.namedNode('http://ex.com/p1'),
          factory.literal('o1', 'en-gb'),
          factory.namedNode('http://ex.com/g1')
        ),
        factory.quad(
          factory.namedNode('http://ex.com/s2'),
          factory.namedNode('http://ex.com/p2'),
          factory.literal('o2', 'en-gb'),
          factory.namedNode('http://ex.com/g3')
        )
      ];
      const source = utils.createArrayStream(quads);
      await utils.waitForEvent(store.import(source), 'end', true);
      const matchedQuads = await utils.streamToArray(store.match());
      should(matchedQuads).have.length(3);
    });

dataFactory.quad(
          dataFactory.namedNode('http://ex.com/s0'),
          dataFactory.namedNode('http://ex.com/p0'),
          dataFactory.literal('1', `${XSD}integer`),
          dataFactory.namedNode('http://ex.com/g0')
        ),
        dataFactory.quad(
          dataFactory.namedNode('http://ex.com/s0'),
          dataFactory.namedNode('http://ex.com/p1'),
          dataFactory.literal('3', `${XSD}integer`),
          dataFactory.namedNode('http://ex.com/g0')
        ),
        dataFactory.quad(
          dataFactory.namedNode('http://ex.com/s0'),
          dataFactory.namedNode('http://ex.com/p2'),
          dataFactory.literal('5', `${XSD}integer`),
          dataFactory.namedNode('http://ex.com/g0')
        )
      ];
      await store.put(quads);
      const query = 'SELECT * WHERE { GRAPH ?g { ?s ?p ?o. FILTER (?o >= 4) } }';
      const bindings = await utils.streamToArray(await store.sparql(query));
      should(bindings).have.length(2);
    });

it('Should filter quads correctly by comparing integers', async function () {
      const XSD = 'http://www.w3.org/2001/XMLSchema#';
      const store = this.store;
      const quads = [
        dataFactory.quad(
          dataFactory.namedNode('http://ex.com/s0'),
          dataFactory.namedNode('http://ex.com/p3'),
          dataFactory.literal('8', `${XSD}integer`),
          dataFactory.namedNode('http://ex.com/g0')
        ),
        dataFactory.quad(
          dataFactory.namedNode('http://ex.com/s0'),
          dataFactory.namedNode('http://ex.com/p0'),
          dataFactory.literal('1', `${XSD}integer`),
          dataFactory.namedNode('http://ex.com/g0')
        ),
        dataFactory.quad(
          dataFactory.namedNode('http://ex.com/s0'),
          dataFactory.namedNode('http://ex.com/p1'),
          dataFactory.literal('3', `${XSD}integer`),
          dataFactory.namedNode('http://ex.com/g0')
        ),
        dataFactory.quad(
          dataFactory.namedNode('http://ex.com/s0'),

factory.quad(
          factory.namedNode('http://ex.com/s0'),
          factory.namedNode('http://ex.com/p0'),
          factory.literal('o0', 'en-gb'),
          factory.namedNode('http://ex.com/g0')
        ),
        factory.quad(
          factory.namedNode('http://ex.com/s0'),
          factory.namedNode('http://ex.com/p1'),
          factory.literal('o1', 'en-gb'),
          factory.namedNode('http://ex.com/g1')
        ),
        factory.quad(
          factory.namedNode('http://ex.com/s2'),
          factory.namedNode('http://ex.com/p1'),
          factory.literal('o2', 'en-gb'),
          factory.namedNode('http://ex.com/g1')
        )
      ];
      await store.put(quads);
      await store.del({ subject: factory.namedNode('http://ex.com/s0') });
      const foundQuads = await store.get({});
      should(foundQuads).have.length(1);
    });
  });

dataFactory.quad(
          dataFactory.namedNode('http://ex.com/s0'),
          dataFactory.namedNode('http://ex.com/p3'),
          dataFactory.literal('8', `${XSD}integer`),
          dataFactory.namedNode('http://ex.com/g0')
        ),
        dataFactory.quad(
          dataFactory.namedNode('http://ex.com/s0'),
          dataFactory.namedNode('http://ex.com/p0'),
          dataFactory.literal('1', `${XSD}integer`),
          dataFactory.namedNode('http://ex.com/g0')
        ),
        dataFactory.quad(
          dataFactory.namedNode('http://ex.com/s0'),
          dataFactory.namedNode('http://ex.com/p1'),
          dataFactory.literal('3', `${XSD}integer`),
          dataFactory.namedNode('http://ex.com/g0')
        ),
        dataFactory.quad(
          dataFactory.namedNode('http://ex.com/s0'),
          dataFactory.namedNode('http://ex.com/p2'),
          dataFactory.literal('5', `${XSD}integer`),
          dataFactory.namedNode('http://ex.com/g0')
        )
      ];
      await store.put(quads);
      const query = 'SELECT * WHERE { GRAPH ?g { ?s ?p ?o. FILTER (?o >= 4) } }';
      const bindings = await utils.streamToArray(await store.sparql(query));
      should(bindings).have.length(2);
    });

it('Should delete matching quads correctly (callback).', async function () {
      const store = this.store;
      const quads = [
        factory.quad(
          factory.namedNode('http://ex.com/s0'),
          factory.namedNode('http://ex.com/p0'),
          factory.literal('o0', 'en-gb'),
          factory.namedNode('http://ex.com/g0')
        ),
        factory.quad(
          factory.namedNode('http://ex.com/s0'),
          factory.namedNode('http://ex.com/p1'),
          factory.literal('o1', 'en-gb'),
          factory.namedNode('http://ex.com/g1')
        ),
        factory.quad(
          factory.namedNode('http://ex.com/s2'),
          factory.namedNode('http://ex.com/p1'),
          factory.literal('o2', 'en-gb'),
          factory.namedNode('http://ex.com/g1')
        )
      ];
      await store.put(quads);

it('Should filter quads correctly by comparing timestamps as integers', async function () {
      const XSD = 'http://www.w3.org/2001/XMLSchema#';
      const store = this.store;
      const quads = [
        dataFactory.quad(
          dataFactory.namedNode('http://ex.com/s0'),
          dataFactory.namedNode('http://ex.com/p2'),
          dataFactory.literal(new Date('2017-01-02T00:00:00Z').valueOf(), `${XSD}integer`),
          dataFactory.namedNode('http://ex.com/g0')
        ),
        dataFactory.quad(
          dataFactory.namedNode('http://ex.com/s0'),
          dataFactory.namedNode('http://ex.com/p3'),
          dataFactory.literal(new Date('2017-01-01T00:00:00Z').valueOf(), `${XSD}integer`),
          dataFactory.namedNode('http://ex.com/g0')
        ),
        dataFactory.quad(
          dataFactory.namedNode('http://ex.com/s0'),
          dataFactory.namedNode('http://ex.com/p0'),
          dataFactory.literal(new Date('2017-01-01T12:00:00Z').valueOf(), `${XSD}integer`),
          dataFactory.namedNode('http://ex.com/g0')
        ),
        dataFactory.quad(
          dataFactory.namedNode('http://ex.com/s0'),
          dataFactory.namedNode('http://ex.com/p1'),
          dataFactory.literal(new Date('2017-01-01T16:00:00Z').valueOf(), `${XSD}integer`),
          dataFactory.namedNode('http://ex.com/g0')
        )
      ];
      await store.put(quads);

it('should remove matching quads correctly', async function () {
      const store = this.store;
      const importQuads = [
        factory.quad(
          factory.namedNode('http://ex.com/s0'),
          factory.namedNode('http://ex.com/p0'),
          factory.literal('o0', 'en-gb'),
          factory.namedNode('http://ex.com/g0')
        ),
        factory.quad(
          factory.namedNode('http://ex.com/s1'),
          factory.namedNode('http://ex.com/p1'),
          factory.literal('o1', 'en-gb'),
          factory.namedNode('http://ex.com/g1')
        ),
        factory.quad(
          factory.namedNode('http://ex.com/s2'),
          factory.namedNode('http://ex.com/p2'),
          factory.literal('o2', 'en-gb'),
          factory.namedNode('http://ex.com/g1')
        )
      ];
      const importStream = utils.createArrayStream(importQuads);
      await utils.waitForEvent(store.import(importStream), 'end', true);
      await utils.waitForEvent(store.removeMatches(null, null, null, factory.namedNode('http://ex.com/g1')), 'end', true);
      const matchedQuads = await utils.streamToArray(store.match());
      should(matchedQuads).have.length(1);
    });
  });

it('should remove streamed quads correctly', async function () {
      const store = this.store;
      const importQuads = [
        factory.quad(
          factory.namedNode('http://ex.com/s0'),
          factory.namedNode('http://ex.com/p0'),
          factory.literal('o0', 'en-gb'),
          factory.namedNode('http://ex.com/g0')
        ),
        factory.quad(
          factory.namedNode('http://ex.com/s1'),
          factory.namedNode('http://ex.com/p1'),
          factory.literal('o1', 'en-gb'),
          factory.namedNode('http://ex.com/g1')
        ),
        factory.quad(
          factory.namedNode('http://ex.com/s2'),
          factory.namedNode('http://ex.com/p2'),
          factory.literal('o2', 'en-gb'),
          factory.namedNode('http://ex.com/g3')
        )
      ];
      const removeQuads = [