13Modules
In this chapter, you'll learn about ES2015's modules, which make it easy to divide your code into small, maintainable pieces and bring them together as needed.
INTRODUCTION TO MODULES
For years, JavaScript programmers either just put their code into the global namespace, or (since the global namespace is crowded) wrapped their code in a wrapper function (a scoping function). Sometimes they'd have that scoping function return an object (sometimes called a namespace object) they assigned to a single global variable (the “revealing module pattern”). In projects of any size, programmers would run into issues with name conflicts, complex dependencies, and splitting the code into appropriately sized files. Those issues led to various different—and incompatible—solutions for defining and combining modules of code, such as CommonJS (CJS), Asynchronous Module Definition (AMD), and variations of them. Multiple incompatible standards make life difficult for programmers, tool builders, library authors, and anyone trying to use modules from different sources.
Thankfully, ES2015 standardized modules for JavaScript, providing mostly common syntax and semantics for ...
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