Manuel Tejeiro Del Río

Testing There is certainly no shortage of tools to choose from when testing your JavaScript, and the list seems to grow longer each day. One of the more popular behavior-driven tools is Jasmine. In Jasmine you use a describe function to create a test suite, but you’re really just creating a JavaScript function. Inside of that function, […]

Implementation As Wikipedia states: “Node.js is a packaged compilation of Google’s V8 JavaScript engine, the libuv platform abstraction layer, and a core library, which is itself primarily written in JavaScript.” Beyond that, it’s worth noting that Ryan Dahl, the creator of Node.js, was aiming to create real-time websites with push capability, “inspired by applications like Gmail”. […]

Apart from a few legacy bits that linger like the alert() function above, JavaScript is an asynchronous language.  When an event fires, all that happens is a new message is added to the queue. No event has the ability to take over the thread. Each event fired must get in the queue and wait its turn to […]

Before going into examples, let’s make sure that we know some basics. I highlighted four types of errors in JavaScript: Syntax errors occur at the interpretation time, they are considered as bugs and can never be handled properly because the code is just wrong by definition: 2. Program error, which is also a bug. For example, trying […]

Events, event handlers and propagation Events are actions or occurrences that happen in the system you are programming — the system produces (or “fires”) a signal of some kind when an event occurs, and also provides a mechanism by which some kind of action can be automatically taken (that is, some code running) when the […]

Objects Syntactically speaking, there are several ways to create an object in JavaScript. But no matter how you create an object, it’s actually abstracting an underlying API called Object.create().   Object Literal Notation Literal objects are great for one-off objects. But if you want to create two or more objects of the same type, they are […]

Variables, Types, and Collections Variables Keyword Scope Mutable Assignment var function yes let block yes const block no New variables in JavaScript are declared using one of three keywords: let, const, or var. JavaScript is case sensitive var is the most common declarative keyword. It does not have the restrictions that the other two keywords […]

Hints for the exam After taking the exam I can give you some hints. It is a very deep technical exam, meaning most of the question give you a piece of code, sometimes quite a lof of lines of code for a single question, and you have to provide the output of that piece of […]

It seems I was right when I posted a few years back that Javascript was going to be a pretty huge thing! (it was easy to guess, anyway). I have been been accepted into the beta program for the Salesforce Certified JavaScript Developer I exam. It is not going to be an easy one because […]