Question

For executing array methods on NodeList objects(Array like) we need to make indirect call on Array.prototype every time.

Can we do something so that node_list.slice(0,1) is possible?

As NodeList inherits methods from Object.prototype, i implemented like below and works
perfectly node_list.slice(0,1)

Object.prototype.slice = function(a,b){ return Array.prototype.slice.call(this,a,b);}

Is there any disadvantage on implementing slice on Object.prototype?

Legacy way to call on Array.prototype:

node_list
[<li>​ test_list1 ​</li>​, <li>​ test_list2 ​</li>​]

Object.prototype.toString.call(node_list)
"[object NodeList]"

var content = Array.prototype.slice.call(node_list,0,1)

content
[<li>​ test_list1 ​</li>​]

Object.prototype.toString.call(content)
"[object Array]"

Answer 1

It’s a bad idea to extend the Object’s prototype for this reason.
Even if you want to extend a built-in prototype, reduce the extension to the necessary parts:

HTMLCollection
NodeList

Prototype methods which don’t show up in a for(.. in ..) loop can be defined as follows:

var slicer = { value: Array.prototype.slice };
Object.defineProperty(HTMLCollection.prototype, 'slice', slicer);
Object.defineProperty(NodeList.prototype, 'slice', slicer);

See also:

• Object.defineProperty

Shortest way (without extending prototypes)

// Equivalent to the question's code
[].slice.apply(node_list,0,1)
// A method to turn a node_list/HTMLCollection in an array (for later use?)
[].slice.call(node_list);