Learning JavaScript Data Structures and Algorithms - Third Edition

Inserting an element in the first position

Suppose we need to add a new element to the array (number -1) and would like to insert it in the first position, not the last one. To do so, first we need to free the first position by shifting all the elements to the right. We can loop all the elements of the array, starting from the last position (value of length will be the  end of the array) and shifting the previous element (i-1) to the new position (i) to finally assign the new value we want to the first position (index 0). We can create a function to represent this logic or even add a new method directly to the Array prototype, making the insertFirstPosition method available to all array instances. The following code represents the logic described ...