Get 1D item with 2D coordinates with 1D array beginning at bottom

How do I get a 1D item which starts at the bottom left of a 2D array after providing 2D coordinates?

var width = 3; // the 2D array width  var height = 3; // the 2D array height  var arr = [0, 1, 2, 3, 4, 5, 6, 7, 8]; // 1D array    console.log(getIndex(0,2));  console.log(getIndex(1,2));  console.log(getIndex(2,2));  console.log(getIndex(0,1));  console.log(getIndex(1,1));  console.log(getIndex(2,1));  console.log(getIndex(0,0));  console.log(getIndex(1,0));  console.log(getIndex(2,0));    //Desired output: 0 1 2 3 4 5 6 7 8      function getIndex(x, y) {    return ... ;   // how????????  }  

To illustrate, here's the 2D array of the 1D array in the code above:

           X           0---2       0     6 7 8  Y  |     3 4 5     2     0 1 2  

https://stackoverflow.com/questions/65768310/get-1d-item-with-2d-coordinates-with-1d-array-beginning-at-bottom January 18, 2021 at 11:06AM