Mastering JavaScript

Chapter 5
ES6 modules
Two separate module systems and different module loaders can be a bit
intimidating. ES6 tries to solve this. ES6 has a proposed module specification that
tries to keep the good aspects of both the CommonJS and AMD module patterns.
The syntax of ES6 modules is similar to CommonJS and the ES6 modules support
asynchronous loading and configurable module loading:
//json_processor.js
function processJSON(url) {
...
}
export function getSiteContent(url) {
return processJSON(url);
}
//main.js
import { getSiteContent } from "json_processor.js";
content=getSiteContent("http://google.com/");
ES6 export lets you export a function or variable in a way similar to CommonJS.
In the code where you want to use this imported function, you use the import
keyword to specify from where you want the dependency to be imported. Once the
dependency is imported, it can be used as a member of the program. We will discuss
in later chapters how you can use ES6 in environments where ES6 is not supported.
The factory pattern
The factory pattern is another popular object creation pattern. It does not require the
usage of constructors. This pattern provides an interface to create objects. Based on
the type passed to the factory, that particular type of object is created by the factory.
A common implementation of this pattern is usually using a class or static method of
a class. The purposes of such a class or method are as follows:
• It abstracts out repetitive operations when creating similar objects
• It allows the consumers of the factory to create objects without knowing the
internals of the object creation
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