The Resource Description Framework (RDF), together with its extension RDF Schema, is a logical formalism that allows formalizing information models in the form of RDF vocabularies and representing propositional information on the Web, embedded in web pages or in the form of special web data sources. OWL extends RDF by adding many additional language elements for expressing constraints, equalities and derived classes and properties in the context of defining vocabularies. Unfortunately, both RDF and OWL have many usability issues.
As in all cases of designing a complex system, no matter if a new building, a new space shuttle, a new computer or a new software application is to be designed, an architecture provides a kind of master plan for defining the structure of the system.
The term "reactive programming" refers to a programming style based on handling "events" of all sorts. App developers are familiar with simple user interface events, such as mouse clicks, and know how to deal with them using their favorite programming language. But there are also other kinds of events an app may have to deal with, such as a state change of an object, an incoming message, the completion of an asynchronuous operation or an exception/error event.
Don't confuse a DOM collection with a JS array: Array functions, such as the forEach looping method, cannot be applied to a DOM collection!
For instance, when you retrieve all rows of an HTML table element, you get an HTMLCollection, which is an array-like object, but not an instance of Array, and therefore the following code does not succeed because the Array method forEach is not defined for an HTMLCollection like myTableEl.rows: