# A designers aid

**jQuery** is a library within javascript that is meant to make tree traversals and handling events like animations easier. Within this library is the `each` method. This method is simply an iterator. It will loop over any iterable *object* or *array* in order to manipulate elements within it. 

# How does it work?

The `jQuery.each` method takes in two parameters: 

1. The first parameter is the array or object on which the method is to be applied
 

2. The second parameter is the **callback**; this is a function that is applied on every element of the array or object. *The callback itself has two parameters*:
   * The first parameter, **position**, is the index of the current element on which the function is to be applied
   * The second parameter, **value**, contains the value at the position given

>**Note:** Keep in mind that if the `each` method is being applied on an array, then the callback will have a number which denotes the index and its corresponding value as arguments. If the method is being run on an object then it will be given a key-value pair as arguments.


# Understanding through example
$$$$
## 1. `each` method on arrays

document.addEventListener("DOMContentLoaded", function () {
  pTag = document.querySelector("div");
  newVal = document.createElement("p");
  pTag.appendChild(newVal);
  
  // The code below creates an array of fruits
  var fruits = ["apple","banana","mango"];
  // The each method is called
  // The first argument passed is the array
  // The second argument is the callback 
  // i is the current index
  // val is the value at that index which the callback returns
  $.each(fruits , function (i, val){
	console.log('At index ' + i + ' the fruit is ' + val);
	});

});

codemirror

console

The each method in jQuery

A designers aid

How does it work?

Understanding through example

1. `each` method on arrays

2. `each` method on a JSON object

The each method in jQuery

A designers aid

How does it work?

Understanding through example

1. each method on arrays

2. each method on a JSON object

1. `each` method on arrays

2. `each` method on a JSON object