Original Array
array = [2, 3, 4, 5, 35];

.map() - Map array items to a new array. This example takes the original array and multiplies each item by 2.

.filter() - Filter array to a new array. This example filters the items that are greater than 4 and creates a new array.

.find() - Find first use of value. This example finds the value of the first item greater than 4 and creates a variable for it.

.findIndex() - Find first use of value and returns the index. This example finds the value of the first item greater than 4, returns its index number and creates a variable for it.

.every() - Test if every item meets a condition. This example tests if every item in the array is greater than 5 and returns a boolean.

.some() - Test if some items meet a condition. This example tests if some of the items in the array are greater than 34 and returns a boolean.

Use the spread syntax to join arrays (...)
array2 = [10,11,12];