1. forEach

• forEach method executes a provided function each array element only once in ascending index order.
• ForEach method is not execute empty elements.
• ForEach method is not return any value. Its return 'undefined'.

2. array.map()

• map method creates new array from calling a function for each array element.
• map method is not execute an empty elements.
• map method returns new array results of function for each array elements.
• map method not affect original array.

3. array.filter()

• 1. filter method creates a new array with all array elements that pass the test condition by provided function.
• 2. If condition fails it return an empty array.
• 3. filter method not affect original array.