Run results for: Array.prototype.slice vs spread operator vs loop 2D

Test name	Executions per second
✓ pre-built array loop	3,860 Ops/sec
spread operator	3,858 Ops/sec
simple loop	3,821 Ops/sec
placement loop	3,804 Ops/sec
constants loop	3,762 Ops/sec
Array.prototype.slice	3,662 Ops/sec

Array.prototype.slice

let param = [];
for (let a = 0; a < 50; a++) {
    param[a] = new Array(50);
    for (let b = 0; b < 50; b++) {
        param[a][b] = Math.random();
    }
}

let ans = [];
for (let i = 0; i < param.length; i++) {
  ans.push(param[i].slice());
}

spread operator

let param = [];
for (let a = 0; a < 50; a++) {
    param[a] = new Array(50);
    for (let b = 0; b < 50; b++) {
        param[a][b] = Math.random();
    }
}

let ans = [];
for (let i = 0; i < 50; i++) {
  ans.push([...param[i]]);
}

simple loop

let param = [];
for (let a = 0; a < 50; a++) {
    param[a] = new Array(50);
    for (let b = 0; b < 50; b++) {
        param[a][b] = Math.random();
    }
}

let ans = [];
for (let i = 0; i < 50; i++) {
  ans.push([]);
  for(let j = 0; j < 50; j++) {
    ans[i].push(param[i][j]);
  }
}

constants loop

let param = [];
for (let a = 0; a < 50; a++) {
    param[a] = new Array(50);
    for (let b = 0; b < 50; b++) {
        param[a][b] = Math.random();
    }
}

let ans = [];
for (let i = 0; i < 50; i++) {
  ans.push([]);
  for(let j = 0; j < 50; j++) {
    ans[i].push(param[i][j]);
  }
}

placement loop

let param = [];
for (let a = 0; a < 50; a++) {
    param[a] = new Array(50);
    for (let b = 0; b < 50; b++) {
        param[a][b] = Math.random();
    }
}

let ans = [];
for (let i = 0; i < 50; i++) {
  ans.push([]);
  for(let j = 0; j < 50; j++) {
    ans[i][j] = param[i][j];
  }
}

pre-built array loop

let param = [];
for (let a = 0; a < 50; a++) {
    param[a] = new Array(50);
    for (let b = 0; b < 50; b++) {
        param[a][b] = Math.random();
    }
}

let ans = new Array(50);
for (let i = 0; i < 50; i++) {
  ans[i] = new Array(50);
  for(let j = 0; j < 50; j++) {
    ans[i][j] = param[i][j];
  }
}

Run results for: Array.prototype.slice vs spread operator vs loop 2D

Compare the new ES6 spread operator with the traditional slice() method

Array.prototype.slice

spread operator

simple loop

constants loop

placement loop

pre-built array loop