promise_all_arrays

 async getClasses () {
        Promise.all([Graph.getSubjectListByPredicateAndObject({
          dataset: this.dataset,
          predicate: this.rdfConstructs.rdf_type.value,
          object: this.rdfConstructs.owl_Class.value
        }), Graph.getSubjectListByPredicate({
          dataset: this.dataset,
          predicate: this.rdfConstructs.rdfs_subClassOf.value
        })]).then(values => {
          let classes = values[0]
          let subclasses = values[1]
          console.log(classes)
          console.log(subclasses)
          // this never works (nor concat, nor classes.push.apply(classes, subclasses)
          Array.prototype.push.apply(classes, subclasses);
          console.log(classes)
          this.classes = classes
        })