JavaScript 实现二维数组的创建

let arr = new Array(3).fill(new Array(4).fill(0));

console.log(arr);

console.log(arr[0] === arr[1]);

[ [ 0, 0, 0, 0 ], [ 0, 0, 0, 0 ], [ 0, 0, 0, 0 ] ]
true

地址指向相同

let arr1 = new Array(3).fill().map(() => new Array(4).fill(0));

console.log(arr1);

console.log(arr1[0] === arr1[1]);

[ [ 0, 0, 0, 0 ], [ 0, 0, 0, 0 ], [ 0, 0, 0, 0 ] ]
false

地址指向不同