let b= Array(100000).fill().map((_, i) => "Hello"+i);
let r=null;
let a = [...b];
while(a.length) r+= a.shift().length;
let a = [...b];
for(i in a) r+= a[i].length;
let a = [...b];
for(x of a) r+= x.length;
let a = [...b];
for (i=0; i<a.length; ++i) r+= a[i].length;
let a = [...b];
a.forEach(x=> r+= x.length);