2次元配列の初期化（ES2015） ref: http://qiita.com/butchi_y/items/db3078dced4592872a9c

es5.js

var x, y;
var tbl = new Array(3);
for(y = 0; y < 3; y++) {
  tbl[y] = new Array(3);
  for(x = 0; x < 3; x++) {
    tbl[y][x] = 0;
  }
}

failed.js

var tbl = (new Array(3)).fill((new Array(3)).fill(0));

file0.js

var arr = (new Array(3)).fill(0);

file3.js

var tbl = (new Array(3)).fill((new Array(3)).fill(0));
tbl[1][1] = 5;
console.log(tbl[1][1]); // => 5
console.log(tbl[2][1]); // => 5

file4.js

var row = (new Array(3)).fill(0);
var tbl = [row, row, row];
row[1] = 5;
console.log(tbl[1][1]); // => 5
console.log(tbl[2][1]); // => 5

method-1.js

var tbl = JSON.parse(JSON.stringify((new Array(3)).fill((new Array(3)).fill(0))));

method-2.js

var tbl = (new Array(3)).fill(0);
tbl.forEach((_, i) => {
  tbl[i] = (new Array(3)).fill(0);
});

method-3.js

var tbl = new Array(3);
for(let y = 0; y < 3; y++) {
  tbl[y] = new Array(3).fill(0);
}