ArrayMethods

ARRAY : An array is a special variable, which can hold more than one value at a time.
Creating an Array
Using an array literal is the easiest way to create a JavaScript Array.

Syntax:
const array_name = [item1, item2, ...];
Example 
const bikes = ["PULSAR", "ACTIVA", "PLEASURE"];

Using the JavaScript Keyword new
The following example also creates an Array, and assigns values to it:
Example
const bikes = new Array["PULSAR", "ACTIVA", "PLEASURE"];

ARRAY METHODS
 toString() : The JavaScript method toString() converts an array to a string of (comma separated) array values.
 Example
 const fruits = ["Banana", "Orange", "Apple", "Mango"];
 fruits.toString()
 Result:
 (4)Banana,Orange,Apple,Mango
 
 join() : The join() method also joins all array elements into a string.
 Example 
 const fruits = ["Banana", "Orange", "Apple", "Mango"];
 fruits.join(" * ")
 Result:
 (4)Banana * Orange * Apple * Mango
 
 shift() : The shift() method removes the first array element and "shifts" all other elements to a lower index.
 Example
 const fruits = ["Banana", "Orange", "Apple", "Mango"];
 fruits.shift();   // Removes "Banana" from fruits
 Result:
 (3)Orange,Apple,Mango

 unshift() : The unshift() method adds a new element to an array (at the beginning), and "unshifts" older elements .
 Example
 const fruits = ["Banana", "Orange", "Apple", "Mango"];
 fruits.unshift("Watermelon");    // Adds "Watermelon" to fruits
 Result:
 (5)['Watermelon','Banana','Orange','Apple','Mango']
 
 push() : The push() method adds a new element to an array (at the end).
 Example
 const fruits = ["Banana", "Orange", "Apple", "Mango"];
 fruits.push("Kiwi");   // Adds "Kiwi" to fruits
 Result:
 (5)['Banana','Orange','Apple','Mango','Kiwi']
 
 pop() : The pop() method removes the last element from an array.
 Example
 const fruits = ["Banana", "Orange", "Apple", "Mango"];
 fruits.pop();  // Removes "Mango" from fruits
 Result:
 (3)['Banana','Orange','Apple']
 
 splice() : The splice() method can be used to add new items to an array.
 Example
 const fruits = ["Banana", "Orange", "Apple", "Mango"];
 fruits.splice(0, 0, "Lemon", "Kiwi");
 Result:
 (6)['Lemon','Kiwi','Banana','Orange','Apple','Mango']
 
 slice() : The slice() method slices out a piece of an array into a new array.
 This example slices out a part of an array starting from array element 1 ("Orange"):
 Example 1 :
 const fruits = ["Banana", "Orange", "Lemon", "Apple", "Mango"];
 const citrus = fruits.slice(1);
 Result:
 (4)'[Orange','Lemon','Apple','Mango']
 Example 2 :
 const fruits = ["Banana", "Orange", "Lemon", "Apple", "Mango"];
 const citrus = fruits.slice(1, 3);
 Result:
 (2)['Orange','Lemon']

 concat() : The concat() method creates a new array by merging (concatenating) existing arrays.
 Example
 const myGirls = ["Cecilie", "Lone"];
 const myBoys = ["Emil", "Tobias", "Linus"];
 // Concatenate (join) myGirls and myBoys
 const myChildren = myGirls.concat(myBoys); 
 Result:
 (5)['Cecilie','Lone','Emil','Tobias','Linus']

ARRAY SORTING
 sort() : The sort() method sorts an array alphabetically.
 Example 1 :
 const fruits = ["Banana", "Orange", "Apple", "Mango"];
 fruits.sort();   // Sorts the elements of fruits;
 Result:
 (4)['Apple','Banana','Mango','Orange']
 Example 2 :
 const names = ["Superstar","Vijay","Akhil","Mahesh","Ganesh"];
 names.sort();
 Result:
 (5)['Akhil','Ganesh','Mahesh','Superstar','Vijay']
 
 reverse() : The reverse() method reverses the elements in an array.
 You can use it to sort an array in descending order:
 Example
 const fruits = ["Banana", "Orange", "Apple", "Mango"];
 fruits.sort();        // First sort the elements of fruits
 fruits.reverse();     // Then reverse the order of the elements
 Result:
 (4)['Orange','Mango','Banana','Apple']