Discussion on: Javascript Array.push is 945x faster than Array.concat 🤯🤔

[Dima]

Seems the problem is not in concat, but in = itself.
As I can see map of concat is even faster than push

console.time('how long');
var arBig = 
[...Array(10000).keys()].map( function(step) {
  return arr1.concat(arr2);
});
console.log(arBig.length);
console.timeEnd('how long');

Plz check jsperf.com/javascript-array-concat...