If you are still reading this, here’s your basic primer on why JavaScript needs modules. If this sounds like an obvious question, you can probably jump to the next section in the article. Module loading and packaging will be covered at another time. This article will focus on ES2015 module syntax and some of its gotchas. Asynchronous and configurable module loading.ES2015 formalizes what CommonJS (the basis for modules in Node.js) and AMD have tried to address in an attempt to take all the strengths and leave out the weaknesses: eeLights = 'Christmas // the decorator is applied hereĬonsole.log(ChristmasTree.Note: This blog post is also available at IBM DeveloperWorks.ĮCMAScript 2015 (formerly known as ES6) introduces a completely new feature and concept to the front-end JavaScript world that strangely has been around for a very long time – modules. The behaviour of the class is modified here Example: // decorator lights is a function which receives the class as an argument Now your CounterApp has dynamically added functionality Without you knowing the implementation details. For example, in your code you simply imported the decorator and added it to your CounterApp class. The functionality of an object can be modified at runtime when using a decorator. Single Responsibility Principle, as it allows functionality to beĭivided between classes with unique areas of concern Why use a decorator? The decorator pattern is often useful for adhering to the Pattern that allows behavior to be added to an individual object,ĭynamically, without affecting the behavior of other objects from the In object-oriented programming, the decorator pattern is a design It is a design pattern used in all object oriented programming languages. A decorator is not just a concept in javascript. The ability to add new behavior at runtime is accomplished by a Decorator object which ‘wraps itself’ around the original object. decorates) an object’s behavior dynamically. What is a decorator?Ī decorator extends (i.e. Decorators are not present in ES6 so the in code you are working with the decorator is probably transpiled to an version of javascript which can be run in any browser.
What is symbol in javascript stands for a decorator.
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