Filter or map nodelists in ES6

Question

What is the most efficient way to filter or map a nodelist in ES6?

Based on my readings, I would use one of the following options:

[...nodelist].filt         


        

Answer 1

TL;DR;

Array.prototype.slice.call(nodelist).filter

The slice() method returns an array. That returned array is a shallow copy of collection (NodeList) So it works faster than Array.from() So it works as fast as Array.from()

Elements of the original collection are copied into the returned array as follows:

• For object references (and not the actual object), slice copies object references into the new array. Both the original and new array refer to the same object. If a referenced object changes, the changes are visible to both the new and original arrays.
• For strings, numbers and booleans (not String, Number and Boolean objects), slice copies the values into the new array. Changes to the string, number or boolean in one array do not affect the other array.

Short explanation regarding arguments

Array.prototype.slice(beginIndex, endIndex)

• takes optional args beginIndex and endIndex. If they are not provided slices uses beginIndex == 0, thus it extracts all the items from the collection

Array.prototype.slice.call(namespace, beginIndex, endIndex)

• takes an object as the first argument. If we use a collection as an object it literally means that we call slice method directly from that object namespace.slice()