javascript object property lookup

Question

Due to object in javascript is associative map (HashMap in other programming languages) does next code

for (var prop in object) {
    if (prop === someConc         


        

Answer 1

This can be tested empirically:

Method 1 takes MUCH longer than Method 2. This is hardly surprising since all of the computing necessary to execute Method 2 is included in Method 1 plus MUCH more.