I am trying to chain multiple methods in Array.
Original array:
this.array = [1, 2, 3, 4, 5, 6];
Clone:
this.array.slice(0);
Change the first element
this.array.splice(0, 0, 10);
Running these individually works.
Combining both:
this.array.slice(0).splice(0, 0, 10);
This doesnot work. Why?
Because this.array.splice(0, 0, 10); will return a new array(containing the removed elements - in this case an empty array since no element is removed) not the source array on which it was called on.
In your case you are using a clone of the original array, so you are loosing the reference to the cloned instance.
So this.array.slice(0) will return a clone on which the .splice(0, 0, 10) is performed(it will update the cloned object) but the splice operation will return a new array(with removed objects) not the cloned instance so we looses reference to it
So the solution is to use a temp reference like
var tmp = this.array.slice(0);
tmp.splice(0, 0, 10)
It doesn't work because the second splice will operate on the return value of the first, and return value of array.splice() is a new array containing the elements that have been removed from the original array.
In short, array.splice() is not suitable for chaining in this way.
sliceinvocation, so you can't see it.splicerun on cloned instance without creating additional arrays?