test run on February 3rd 2017

$ node -v
v6.9.4

$ time node example1.js # with “let”
real 0m0.800s
user 0m0.796s
sys 0m0.000s

$ time node example2.js # with “let”
real 0m2.119s
user 0m2.108s
sys 0m0.012s

$ time node example1.js # with “var”
real 0m0.322s
user 0m0.296s
sys 0m0.008s

$ time node example2.js # with “var”
real 0m1.557s
user 0m1.552s
sys 0m0.000s