# Nodeschool.io JavaScripting

## Introduction

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## Variables

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## Strings

* Looks like convention in JavaScript is to use single quotes.

## String Length

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## Revising Strings

* JavaScript has a `.replace()` method that takes two arguments. The first argument is an existing substring and the second is the string that will replace it.

## Numbers

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## Rounding Numbers

* To round numbers in JavaScript we use the `Math` object along with the `.round()` method and pass it in the float we want rounded.

## Number to String

* We use the `.toString()` method to convert a number to a string.

## If Statement

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## For Loop

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## Arrays

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## Array Filtering

* We use the `.filter()` method to filter an array based on a condition.
```js
var filtered = numbers.filter(function(num) {
  return num % 2 === 0;
});
```

## Accessing Array Values

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## Looping Through Arrays

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## Objects

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## Object Properties

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## Functions

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## Function Arguments

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## Scope

* Scope is the set of variables, objects, and functions you have access to.
* JavaScript has two scopes: global and local.
* A variable that is declared outside a function definition is a global variable, and its value is accessible and modifiable throughout your program.
* A variable that is declared inside a function definition is local. It is created and destroyed everytime the function is executed, and it cannot be accessed by any code outside the function.
* Functions defined inside other functions, known as nested functions, have access to their parent function's scope.
* IIFE, Immediately Invoked Function Expression, is a common pattern for creating local scopes.
```js
(function() {
})();
```