Prototypal Inheritance
Douglas Crockford www.crockford.com Five years ago I wrote Classical Inheritance in JavaScript (Chinese Italian Japanese). It showed that JavaScript is a class-free, prototypal language, and that it has sufficient expressive power to simulate a classical system. My journey was circuitous because JavaScript itself is conflicted about its prototypal nature. new () produces a new object that inherits from .prototype This indirection was intended to make the language seem more familiar to classically trained programmers, but failed to do that, as we can see from the very low opinion Java programmers have of JavaScript. Fortunately, it is easy to create an operator that implements true prototypal inheritance. function object(o) { function F() {} F.prototype = o; return new F(); } The object function untangles JavaScript's constructor pattern, achieving true prototypal inheritance. So instead of creating classes, you make prototype objects, and then use the object function to make new instances.
Classical Inheritance in JavaScript
Douglas Crockford www.crockford.com And you think you're so clever and classless and free — John Lennon JavaScript is a class-free, object-oriented language, and as such, it uses prototypal inheritance instead of classical inheritance. This can be puzzling to programmers trained in conventional object-oriented languages like C++ and Java. But first, why do we care about inheritance at all? The second reason is code reuse. To demonstrate this, we will introduce a little sugar which will let us write in a style that resembles a conventional classical language. Classical Inheritance First, we will make a Parenizor class that will have set and get methods for its value, and a toString method that will wrap the value in parens. The syntax is a little unusual, but it is easy to recognize the classical pattern in it. So now we can write myParenizor = new Parenizor(0); myString = myParenizor.toString(); As you would expect, myString is "(0)". The inherits method is similar to Java's extends. Sugar
syntax - What does "use strict" do in JavaScript, and what is the reasoning behind it?
Understanding JavaScript Prototypes.
(en Español, русском, 中文) JavaScript’s prototype object generates confusion wherever it goes. Seasoned JavaScript professionals, even authors frequently exhibit a limited understanding of the concept. What is a prototype? A prototype is an object from which other objects inherit properties Can any object be a prototype? Yes. Which objects have prototypes? Every object has a prototype by default. OK back up, what is an object again? An object in JavaScript is any unordered collection of key-value pairs. You said every object has a prototype. Forget everything you learned about the prototype property – it’s probably the biggest source of confusion about prototypes. Ok fine, but false is a primitive, so why does false. When a primitive is asked for it’s prototype it will be coerced to an object. I want to use prototypes for inheritance. But the real power of prototype is seen when multiple instances share a common prototype. So is this where constructors come in? Yes. OK. Example please? Like this:
The Design of Code: Organizing JavaScript
Great design is a product of care and attention applied to areas that matter, resulting in a useful, understandable, and hopefully beautiful user interface. But don’t be fooled into thinking that design is left only for designers. There is a lot of design in code, and I don’t mean code that builds the user interface—I mean the design of code. Well-designed code is much easier to maintain, optimize, and extend, making for more efficient developers. There are three high-level, language-agnostic aspects to code design that are particularly important. System architecture—The basic layout of the codebase. In looser languages, specifically JavaScript, it takes a bit of discipline to write well-designed code. One approach I’m fond of consists of a tried-and-true software design pattern, the module pattern, whose extensible structure lends itself to a solid system architecture and a maintainable codebase. The module pattern#section1 Building a module#section2 jQuery plugins#section3 Options#section4
oop - JavaScript private methods
Introduction to Object-Oriented JavaScript
Object-oriented to the core, JavaScript features powerful, flexible OOP capabilities. This article starts with an introduction to object-oriented programming, then reviews the JavaScript object model, and finally demonstrates concepts of object-oriented programming in JavaScript. This article does not describe the newer syntax for object-oriented programming in ECMAScript 6. JavaScript review If you don't feel confident about JavaScript concepts such as variables, types, functions, and scope, you can read about those topics in A re-introduction to JavaScript. Object-oriented programming Object-oriented programming (OOP) is a programming paradigm that uses abstraction to create models based on the real world. OOP envisions software as a collection of cooperating objects rather than a collection of functions or simply a list of commands (as is the traditional view). Terminology Namespace A container which lets developers bundle all functionality under a unique, application-specific name. Class
Introducing Prism: An awesome new syntax highlighter
For the past three weeks, on and off, I’ve been working on releasing Dabblet’s syntax highlighter as standalone, since many people had requested it. Zachary Forrest suggested the name “Prism” and I liked it so much I decided to go with it, even though there is an abandoned Mozilla project with the same name. I ended up refactoring and extending it so much that I will need to backport it to Dabblet one of these days! This doesn’t mean I bloated it, the core is still a tiny 1.5KB minified & gzipped. It just means it’s more awesome. In certain ways, Prism is better than any other syntax highlighter I’ve seen: It’s tiny. However, there are some limitations too: Pre-existing HTML in the code block will be stripped off. Enjoy: prismjs.com
Implementing Private and Protected Members in JavaScript — Philip Walton
Privacy has been a complicated issue throughout JavaScript’s history. While it’s always been possible to meet even the most stringent privacy needs (the myriad of compile-to-js languages proves this), the extraneous ceremony required to really do it right is often too much of a turn-off for most developers — especially to those coming from other languages where privacy is built in. In JavaScript we like to prefix our private members with an underscore to let other developers know not to touch them. In fact, many of the more popular JavaScript style guides (airbnb, Dojo, aloha) recommend this. But unless you have a way to enforce such a convention, it can never really be trusted. Thought leaders in the JavaScript community have long warned against fake privacy. Do not use _ (underbar) as the first character of a name. Despite the warnings, a quick search on Github will show that this advice isn’t being taken seriously. Privacy in JavaScript Today function Car() { this. A Step Closer
