LOGANATHAN VELSAMY

What is Event delegation? Event delegation is Javascript as it relates to the DOM. It basically means that if you attach an event listener to a DOM element that listener is not only firing on that DOM element. It's actually firing on every children in that. So, for instance if you have a navigation and so you've got an unordered list you've got list items and then you've got anchor tags inside that navigation what you have. If you add an event listener to the ul element in essence you're actually adding event listener to all of the children as well. In short, JS event listeners fir not only on a single DOM element but on all its descendants. What is Event Bubbling? It's actually inverse of Event delegation. Also known as propagation, events on an DOM element will bubble up and also fire on all parents.  What's the difference between "target" and "currentTarget"? target is the actual element that triggered the event for example clicked, wh

It still surprises me just how many times I come across misconceptions around Micro Services and APIs. Often hearing phrases like micro services are fine grained web services or API is themselves are equivalent to micro services. These all sort of show fundamental misconceptions under the covers. So, I've written this just to really break that out and explain about what the key differences are in those two concepts. What is an API? An API, fundamentally Application Programming Interface, that is an interface. It's a way of making requests into a component. So it's the route that you go in to make those requests. In modern use that typically means a REST API, that's a call made using HTTP protocol using JSON data as the payload. What are Micro Services? So let's ensure we also have a clear crisp definition on what a micro service architecture really is. Micro-Services architecture is about breaking down large silo applications into smaller components. That are more m

What is a micro service? Small, individually, independently deployable application components that are self-contained and exposed through lightweight http based APIs. Here the independence of the of those components is really important because it has lot of ramifications in terms of how manage large-scale deployments of this architecture. Some people may say micros services are contrary to service oriented architecture. Actually, that's not true, Micro services are extension or evolution of service oriented architecture. The same principles still hold true but then it fixes lots of problems that were there in the service oriented architecture like large ESBs (Enterprise service bus), unwieldy configurations and scalability issues. It breaks that down into small reusable components that now you can scale individually or you can manage individually, so it gives lot more flexibility. Why IT industry has moving towards Micro Services? Well, obviously Agile and Scrum are big factor in t