Splice on the other hand has a slightly different signature and it does modify the original array by removing and/or replacing elements in it. Slice() returns a new array containing the elements extracted, as also seen above in the embedded environment. Another term to understand is deep copy, which, unlike the previously mentioned shallow copy, does create a separate memory location and therefore an update to the original assignment will not update the reference. That means that since we are working with a reference, updating the values in the original assignment will also update the reference. Shallow copy is when we copy a reference variable to a new variable using the variable assignment operator ( =). Also note that slice() will not modify the original array:

Please note that the index specified at end is not included in the new array. With slice() we can return a so called shallow copy of an array based on the start and end parameters, which are essentially index locations. The signature specifies two optional parameters: slice (start, end ) Let's start with the slice() method first. Their functionality is very similar, however there are some critical differences between the two. Personally, I always mix-up two array methods in particular: slice and splice. We can iterate through arrays, push elements, pop values (remove and return the last element) and slice and dice the array as we see fit. Working with arrays in JavaScript is a fairly common task and the language provides us developers with a myriad of methods.

Slice and splice in javascript