What for

Convert array like object to array, for example to unlock reduce(), map(), filter()...

Fast and very straight forward.
Working with everything what have a .length:

Benchmark

[https://jsperf.com/nodelist-to-array/27]

Code and usage

function nodeListToArray(nodeList){
var i = nodeList.length
var arr = new Array(i)
while(i--){ arr[i] = nodeList[i] }
return arr
}

// example of usage:
nodeListToArray(document.querySelectorAll('div')).map(...)

Prototype

On top of that fancy addition,
but working only with NodeList's:

NodeList.prototype.toArray = function(){
return nodeListToArray(this)
}

// example of usage:
document.querySelectorAll('div').toArray().filter(...)

Instalation

npm install nodelist-to-array