const mil = 1000000; 
const arr = Array(mil);

console.time('⏲️')


for (let i = 0; i < mil; i++) { }  // 1.6ms

for (const v of arr) {}  // 11.7ms

arr.forEach(v => v) // 2.1ms

for (let i = mil; i > 0; i--) {} // 1.5ms

console.timeEnd('⏲️');