deletedurationtest (npm): tests duration time of deleting object's property and array's elements by means of different instruments: delete o[pName]; or Object.defineProperty(o,pName,{enumerable:false}); or o[pName] = undefined; etc. 
Keywords: test operation time|delete obj.property|obj.property=undefined|Object.defineProperty(o,pName,{enumerable:false})|array's element delete time|object's property delete time test