Interchange the diagonal of a matrix in typescript

Ts program for Interchange the diagonal of a matrix. Here mentioned other language solution.

/*
  TypeScript program for
  Swap diagonal elements of matrix using recursion
*/
class Exchange
{
	// Method which are perform swap operation
	// Here x and y indicate start and end rows
	// p and q indicates start and end columns
	public static swapDiagonal(matrix: number[][], 
  		x: number, y: number, p: number, q: number)
	{
		if (x >= y || p >= q)
		{
			return;
		}
		var temp = matrix[x][p];
		// Swap the element value
		matrix[x][p] = matrix[x][q];
		matrix[x][q] = temp;
		temp = matrix[y][p];
		// Swap the element value
		matrix[y][p] = matrix[y][q];
		matrix[y][q] = temp;
		Exchange.swapDiagonal(matrix, x + 1, 
                              y - 1, p + 1, q - 1);
	}
	// Display matrix elements
	public static showMatrix(matrix: number[][])
	{
		console.log(matrix);
	}
	public static main()
	{
		// Define matrix element
		var matrix: number[][] = [
			[1, 2, 3, 4],
			[5, 6, 7, 8],
			[9, 10, 11, 12],
			[13, 14, 15, 16]
		];
		// Assume N X N matrix
		var n = matrix.length;
		// Display element
		Exchange.showMatrix(matrix);
		// interchange request
		Exchange.swapDiagonal(matrix, 0, n - 1, 0, n - 1);
		// Display element
		Exchange.showMatrix(matrix);
	}
}
Exchange.main();
/*
 file : code.ts
 tsc --target es6 code.ts
 node code.js
 */

Output

[ [ 1, 2, 3, 4 ],
  [ 5, 6, 7, 8 ],
  [ 9, 10, 11, 12 ],
  [ 13, 14, 15, 16 ] ]
[ [ 4, 2, 3, 1 ],
  [ 5, 7, 6, 8 ],
  [ 9, 11, 10, 12 ],
  [ 16, 14, 15, 13 ] ]