spread vs unshift

spread vs unshift.js

// spread.js
let a = [];

console.time('1');
for (let i = 0; i < 100; i++) {
  const res = [];
  for (let j = 0;j<5;j++) {
    res.push(j);
  }
  a = [...res, ...a];
}
console.timeEnd('1');
console.log(a[100]);


//unshift.js
let a = [];

console.time('1');
for (let i = 0; i < 100; i++) {
  const res = [];
  for (let j = 0;j<5;j++) {
    res.push(j);
  }
  a.unshift(...res);
}
console.timeEnd('1');
console.log(a[100]);