In Javascript world arrays is referred to as an Object , hence it can hold different datatypes inside it.

Advantages of Array

• Arrays represent multiple data items of the same type using a single name
• In arrays, the elements can be accessed randomly by using the index number
• Arrays allocate memory in contiguous memory locations for all its elements

There are 3 ways to construct array in JS.

By array Literal

The syntax of creating array using array literal is given below:

let arr1 = ['a' , 'b' , 3 , 4]

By using 'new' keyword

JavaScript array constructor (new keyword)

Indexing in Array

JavaScript arrays are zero-indexed: the first element of an array is at index 0 , the second is at index 1 , and so on — and the last element is at the value of the array's length property minus 1

So you can see here the first value of an arrays has index 0 , second value has index 1 and so on.

Last index = array.length - 1

Methods to Manupulate Array

• .concat()
Consider we have 2 different arrays , arr1 and arr2. So if we want to join two arrays and save those values in new array then we use this method.

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• .sort()
The sort() sorts the elements of an array. The sort() overwrites the original array. The sort() sorts the elements as strings in alphabetical and ascending order.

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• .map()
map() creates a new array from calling a function for every array element. map() calls a function once for each element in an array. map() does not execute the function for empty elements. map() does not change the original array.

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• .slice()
The slice() method returns selected elements in an array, as a new array. The slice() method selects from a given start, up to a (not inclusive) given end. The slice() method does not change the original array.

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• .splice()
The splice() method adds and/or removes array elements. The splice() method overwrites the original array.
syntax
array.splice(index, howmany, item1, ....., itemX)

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• .fill()
The fill() method fills specified elements in an array with a value. The fill() method overwrites the original array. Start and end position can be specified. If not, all elements will be filled.
syntax
array.fill(value, start, end)

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• .toString()
The toString() method returns a string with array values separated by commas. The toString() method does not change the original array.
syntax
array.toString()

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