Explore the basics of JavaScript in greater detail to solve real-world problems.

Zero to Hero in JavaScript

This module aims to teach us how to write cleaner, more modular, and more scalable code in JavaScript by giving us an understanding of object-oriented programming (OOP). We'll start with the basics of object-oriented programming and build up to more advanced concepts such as data protection and inheritance. Along the way, we'll learn how each concept applies to JavaScript in particular, as well as how various JavaScript features make it a suitable language for object-oriented programming.

JavaScript: A Deep Dive

# Background
In this lesson, we will start by defining a module and then learn scope in terms of modules.

# Introduction

**Modules** are files of JavaScript code. They usually contain a class or library of functions for a specific task. These modules break our programs down into smaller parts, making it easier to manage. The illustration below outlines how to break a large file of code into modular chunks.

Previously, we assumed that any variable *declared* outside the functions would be in the global scope and thus would be *accessible* by all scopes. However, in **module scope**, a variable from one module can be in global scope within the module but may not be *accessible* to another module unless explicitly written in the two modules. Module scopes use `import` and `export` keyword to import variables from another module or *export* a variable for other modules.


## Syntax for import/export
To *import* a variable from a **module**, use the following syntax.

```JavaScript
import {variable_names} from "./module_name";
```
Using the keyword `import`, we *import* all variables named in the curly brackets `{}` from the module name as string after the keyword `from`.

Meanwhile, for the *import* to be successful, the corresponding module needs to *export* the variables too. Here is the  syntax:

```JavaScript
export {variable_names};
```

To *export* a variable and make it *available* to all modules, use the `export` keyword and follow it by the list variable names we want to *export* encapsulated in curly brackets `{}`.

Now, study the following code in action.

Introduction to module scope in JavaScript.

Module Scope

Background

Introduction