function processNoProperty(a) { var total = 0; for (var i = 0; i < a.length; i++) { var sa = a[i]; for (var j = 0; j < sa.length; j++) total += sa[j]; } assertEq(total, 22); } var literalArray = [ [1,2,3,4], [1.5,2.5,3.5,4.5] ]; var jsonArray = JSON.parse(`[ [1,2,3,4], [1.5,2.5,3.5,4.5] ]`); for (var i = 0; i < 1000; i++) { processNoProperty(literalArray); processNoProperty(jsonArray); } function processWithProperty(a) { var total = 0; for (var i = 0; i < a.length; i++) { var sa = a[i].p; for (var j = 0; j < sa.length; j++) total += sa[j]; } assertEq(total, 22); } var literalPropertyArray = [ {p:[1,2,3,4]}, {p:[1.5,2.5,3.5,4.5]} ]; var jsonPropertyArray = JSON.parse(`[ {"p":[1,2,3,4]}, {"p":[1.5,2.5,3.5,4.5]} ]`); for (var i = 0; i < 1000; i++) { processWithProperty(literalPropertyArray); processWithProperty(jsonPropertyArray); }