Beautiful JavaScript

CHAPTER ONE

Beautiful Mixins

Angus Croll

Developers love to create overly complex solutions to things that aren’t really problems.

Thomas Fuchs

In the beginning there was code, and the code was verbose, so we invented functions that the code might be reused. But after a while there were also too many functions, so we looked for a way to reuse those too. Developers often go to great lengths to apply “proper” reuse techniques to JavaScript. But sometimes when we try too hard to do the right thing, we miss the beautiful thing right in front of our eyes.

Classical Inheritance

Many developers schooled in Java, C++, Objective-C, and Smalltalk arrive at JavaScript with an almost religious belief in the necessity of the class hierarchy as an organizational tool. Yet humans are not good at classification. Working backward from an abstract superclass toward real types and behaviors is unnatural and restrictive—a superclass must be created before it can be extended, yet classes closer to the root are by nature more generic and abstract and are more easily defined after we have more knowledge of their concrete subclasses. Moreover, the need to tightly couple types a priori such that one type is always defined solely in terms of another tends to lead to an overly rigid, brittle, and often ludicrous model (“Is a button a rectangle or is it a control? Tell you what, let’s make Button inherit from Rectangle, and Rectangle can inherit from Control…no, wait a minute…”). If we don’t get it right ...