Javascript中的高阶函数

Question

I am trying to use higher-order functions to fills a 3x3 2d array. To be specific, i need to use array.map function to finish this. so far my code is:

    function Matrix(m,n){
      var mat = Array.apply(null, new Array(m)).map(
       Array.prototype.valueOf,
       new Array(n)
     );
     return mat;
    }
    restaurants = Matrix(3,3);
    restaurants.map(
      function(row,i){
        return row.map(function(cell,j){
           return new BorderedCell(ToString(ancestry[i][j]));
           });
      });

There is no output when I try to display restaurants. it seems like the code stoped at

    function(row,i){}

and won't go further.

How can I fix this? Any help will be appreciated.

Edit: I am trying to fill A 2D array with object BorderedCell. My problem is I don't know how to use double mapping to go through the whole matrix, which I supposed to do.

Answer 1

If expected result of restaurants is [[0,1,2],[0,1,2],[0,1,2]] you can use Array.from() , Array.prototype.keys()

 function arr(len) { return Array.from(Array(len).keys()) } function Matrix(m, n) { return arr(m).map(arr.bind(null, n)); } var restaurants = Matrix(3, 3); console.log(restaurants);