Category

JavaScript

Learn Meteor.js Properly

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·October 9, 2014

At the end of this article, I outline two comprehensive study guides to help you learn Meteor properly. The study guides are for both beginners and seasoned developers. The first study guide, which uses a book, a paid screencast, and some free online resources, teaches you how to build a sophisticated, modern social-media web application with Meteor. And the second study guide, which uses only free resources (one affordable screencast and free online resources), is just as instructive as the first, though you won’t build a specific web application throughout the course.

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First, I give a comprehensive Meteor overview, in which I discuss just about everything you want and need to know about Meteor before you commit to investing your time and other resources in this still burgeoning though exceptional technology.

Time to read the Meteor Overview:

14 minutes

What You Will Learn in this Meteor Overview

I explain exactly what Meteor is, how it differs from typical JavaScript frameworks, what it offers developers specifically, its alternatives and contemporaries, whether you should be excited or skeptical about it, and where to find Meteor jobs. I also enumerate some of the endorsements written by Meteor converts, and I explore the justifiable criticisms, known limitations, and frequently asked questions that many have raised about Meteor. You will learn all this and much more.

I am honored that you have joined me and I am hopeful you will find this article helpful and illuminating and the accompanying study guides and recommended resources sufficiently instructive.

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Beautiful JavaScript: Easily Create Chainable (Cascading) Methods for Expressiveness

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·August 13, 2013

(Part of the “12 Powerful JavaScript Tips” Series)

Prerequisites:
— Understand JavaScript’s “this” With Ease
— JavaScript Objects in Detail

Chaining Methods, also known as Cascading, refers to repeatedly calling one method after another on an object, in one continuous line of code. This technique abounds in jQuery and other JavaScript libraries and it is even common in some JavaScript native methods.

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Writing code like this:

$("#wrapper").fadeOut().html("Welcome, Sir").fadeIn();

or this:

str.replace("k", "R").toUpperCase().substr(0,4);

is not just pleasurable and convenient but also succinct and intelligible. It allows us to read code like a sentence, flowing gracefully across the page. It also frees us from the monotonous, blocky structures we usually construct.

We will spend the next 20 minutes learning to create expressive code using this cascading technique. To use cascading, we have to return this (the object we want subsequent methods to operate on) in each method. Let’s quickly learn the details and get back to eating, or watching YouTube videos, or reading Hacker News, or working and browsing, or working and focusing.

Let’s create all of our “chainable” code within an object, along with a local data store. Note that in a real-world app we will likely store the data in a database, but here we are just saving it in a variable.

// The data store: var usersData = [ {firstName: "tommy",
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JavaScript’s Apply, Call, and Bind Methods are Essential for JavaScript Professionals

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·July 10, 2013

Prerequisite:
— Understand JavaScript’s “this” With Ease, and Master It.
— JavaScript Objects
— Understand JavaScript Closures
(This is an intermediate to advanced topic)

Duration: About 40 minutes.

Functions are objects in JavaScript, as you should know by now, if you have read any of the prerequisite articles. And as objects, functions have methods, including the powerful Apply, Call, and Bind methods. On the one hand, Apply and Call are nearly identical and are frequently used in JavaScript for borrowing methods and for setting the this value explicitly. We also use Apply for variable-arity functions; you will learn more about this in a bit.

On the other hand, we use Bind for setting the this value in methods and for currying functions.

We will discuss every scenario in which we use these three methods in JavaScript. While Apply and Call come with ECMAScript 3 (available on IE 6, 7, 8, and modern browsers), ECMAScript 5 (available on only modern browsers) added the Bind method. These 3 Function methods are workhorses and sometimes you absolutely need one of them. Let’s begin with the Bind method.

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16 JavaScript Concepts JavaScript Professionals Must Know Well

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·July 9, 2013

(Essential JavaScript Concepts for Modern JavaScript Development )

If you plan to work as JavaScript Professional, you must know some JavaScript concepts and JavaScript-related web-development technologies, particularly as a modern JavaScript developer. If you know the 16 concepts enumerated below, you have the skill necessary to build world-class modern JavaScript web applications, and you are set for the near future—0 to 3 years.

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I will expound on each of these sixteen concepts, and I am hopeful all of us will have become better JavaScript programmers by the time we get through all of them. I have completed most of the 16 concepts with just a few more to go, so keep reading and learning. And sign up for the newsletter to get the latest updates.

I trust you have learned JavaScript properly or you already know JavaScript enough to build a simple JavaScript-only web application. While the 16 concepts note below are neither complex nor difficult, you will understand them best if you already know at least some basic JavaScript.

The sixteen concepts that every modern JavaScript developer should know well follow:

  1. JavaScript Objects in Detail
  2. JavaScript Prototype in Plain, Detailed Language
  3. JavaScript Variable Scope and Hoisting Explained
  4. Understand JavaScript Closures With Ease
  5. Understand JavaScript Callback (Higher-Order) Functions
  6. Understand JavaScript’s “this” With Clarity,
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Understand JavaScript’s “this” With Clarity, and Master It

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·July 5, 2013

(Also learn all the scenarios when this is most misunderstood.)

Prerequisite: A bit of JavaScript.
Duration: about 40 minutes.

The this keyword in JavaScript confuses new and seasoned JavaScript developers alike. This article aims to elucidate this in its entirety. By the time we make it through this article, this will be one part of JavaScript we never have to worry about again. We will understand how to use this correctly in every scenario, including the ticklish situations where it usually proves most elusive.

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We use this similar to the way we use pronouns in natural languages like English and French. We write, “John is running fast because he is trying to catch the train.”

Note the use of the pronoun “he.” We could have written this: “John is running fast because John is trying to catch the train.” We don’t reuse “John” in this manner, for if we do, our family, friends, and colleagues would abandon us. Yes, they would. Well, maybe not your family, but those of us with fair-weather friends and colleagues. In a similar graceful manner, in JavaScript, we use the this keyword as a shortcut, a referent; it refers to an object; that is, the subject in context, or the subject of the executing code. Consider this example:

var person = { firstName: "Penelope",
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OOP In JavaScript: What You NEED to Know

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·March 19, 2013

(Object Oriented JavaScript: Only Two Techniques Matter)

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Prerequisite:
JavaScript Objects in Detail
JavaScript Prototype

Object Oriented Programming (OOP) refers to using self-contained pieces of code to develop applications. We call these self-contained pieces of code objects, better known as Classes in most OOP programming languages and Functions in JavaScript. We use objects as building blocks for our applications. Building applications with objects allows us to adopt some valuable techniques, namely, Inheritance (objects can inherit features from other objects), Polymorphism (objects can share the same interface—how they are accessed and used—while their underlying implementation of the interface may differ), and Encapsulation (each object is responsible for specific tasks).

In this article, we are concerned with only Inheritance and Encapsulation since only these two concepts apply to OOP in JavaScript, particularly because, in JavaScript, objects can encapsulate functionalities and inherit methods and properties from other objects. Accordingly, in the rest of the article, I discuss everything you need to know about using objects in JavaScript in an object oriented manner—with inheritance and encapsulation—to easily reuse code and abstract functionalities into specialized objects.

We will focus on only the best two techniques1 for implementing OOP in JavaScript. Indeed, many techniques exist for implementing OOP in JavaScript, but rather than evaluate each, I choose to focus on the two best techniques: the best technique for creating objects with specialized functionalities (aka Encapsulation) and the best technique for reusing code (aka Inheritance).

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Understand JavaScript Callback Functions and Use Them

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·March 4, 2013

(Learn JavaScript Higher-order Functions, aka Callback Functions)

In JavaScript, functions are first-class objects; that is, functions are of the type Object and they can be used in a first-class manner like any other object (String, Array, Number, etc.) since they are in fact objects themselves. They can be “stored in variables, passed as arguments to functions, created within functions, and returned from functions”1.
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Because functions are first-class objects, we can pass a function as an argument in another function and later execute that passed-in function or even return it to be executed later. This is the essence of using callback functions in JavaScript. In the rest of this article we will learn everything about JavaScript callback functions. Callback functions are probably the most widely used functional programming technique in JavaScript, and you can find them in just about every piece of JavaScript and jQuery code, yet they remain mysterious to many JavaScript developers. The mystery will be no more, by the time you finish reading this article.

Callback functions are derived from a programming paradigm known as functional programming. At a fundamental level, functional programming specifies the use of functions as arguments. Functional programming was—and still is, though to a much lesser extent today—seen as an esoteric technique of specially trained, master programmers.

Fortunately, the techniques of functional programming have been elucidated so that mere mortals like you and me can understand and use them with ease.

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Learn Intermediate and Advanced JavaScript

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·February 25, 2013

(Learn Intermediate and Advanced JavaScript Concepts and Techniques in 2 Weeks)

Prerequisite:
You have completed this course: Learn JavaScript Properly (For NON-JavaScript programmers and First-time Programmers)

Or you already know the following JavaScript concepts well:
— Simple Data Types, Reference Types, Operators, and Objects (in Detail)
— Variable Scope and Hoisting, Expressions, Statements, and JSON
— DOM, The Window Object, JavaScript Events, and Handling Errors
— Functions, Function Properties, Function Expression, and AJAX
— Basic Regular Expressions and Modules

Duration:
2 Weeks

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I submit to you an instructive course on intermediate and advanced JavaScript. The skills you will learn in this course of study will free you from the constrains of using the limited JS techniques you have been using to develop JS applications, and they will give you new insights and new techniques—a Jedi’s temperament and stature—to program JS applications with ease, efficiency, and precision.

If you are new to JavaScript and you are an experienced programmer in another language such as Java, Python, ActionScript, Rails, and PHP, it is important that you learn JavaScript properly. JavaScript has many idiosyncrasies and uncommon concepts that you must know well before you follow this Intermediate to Advanced JavaScript course.

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How to Learn JavaScript Properly

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·February 24, 2013

Learn JavaScript Properly (For Beginners and Experienced Programmers)

This study guide, which I also refer to as a course outline and a road map, gives you a structured and instructive outline for learning JavaScript properly. In fact, you will find two study guides below, one for absolute beginners and the other for experienced programmers and web developers.

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You do want to learn JavaScript. I presume you are here for that reason, and you have made a wise decision. For if you want to develop modern websites and web applications (including an internet startup), or if you want a high-paying developer job ($75K to $250K+), JavaScript is undoubtedly the best web-development language to learn today, unless you want to develop native iOS or Android apps exclusively. And while there exist ample online resources to teach you JavaScript, finding the most efficient and beneficial method to learn the “language of the web” can be a frustrating endeavor. This study guide streamlines and simplifies the process; it has proven successful in helping thousands, and thousands more read and follow it each day.

Study Groups
People have started study groups for this study guide. You can find such groups on Reddit here and here, and other places, including Code Crew Meetup.

What You will Learn

You will learn the JavaScript language (up to advanced-intermediate,

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12 Simple (Yet Powerful) JavaScript Tips

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·February 20, 2013

(For Badass JavaScript Development)

NOTICE: I have written only 2 of the 12 tips so far, but I plan to post all 12 Powerful Tips eventually.

I provide you with 12 simple, yet powerful, JavaScript tips and detailed explanation of each. These are techniques that all JavaScript programmers can use now; you needn’t be an advanced JavaScript developer to benefit from these tips. After you read all of the detailed explanations of how each technique works and when to use it, you will have become a more enlightened JavaScript developer, if you aren’t already one.

Indeed, notable JavaScript masters and enlightened JavaScript developers have been using many of these techniques to write powerful, efficient JavaScript. And in a bit, you will, too.

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  1. Powerful JavaScript Idiomatic Expressions With && and ||

    You see these idiomatic expressions in JavaScript frameworks and libraries. Let’s start off with a couple of basic examples:

    Example 1: Basic “short circuting” with || (Logical OR)
    To set default values, instead of this:

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