Javascript, trying to add a line brake within a while loop

Need to create a chessboard with the following rule set:

Write a program that creates a string that represents an 8×8 grid, using newline characters to separate lines. At each position of the grid there is either a space or a "#" character. The characters should form a chessboard.

Passing this string to console.log should show something like this:

 # # # #
# # # # 
 # # # #
# # # # 
 # # # #
# # # # 
 # # # #
# # # # 

Here is the code i wrote for it:

    var chessBoardSize = 8;
        var chessBoard = " ";
        var lineBreakCount = 0;

        while (chessBoard.length <= chessBoardSize * chessBoardSize) {

            lineBreakCount++;

            if (lineBreakCount === chessBoardSize) {
                chessBoard += "\n";
                lineBreakCount = 0;
            }

            if (chessBoard.slice(-1) === " ") {
                chessBoard = chessBoard + "#";
            } else if (chessBoard.slice(-1) === "#") {
                chessBoard = chessBoard + " ";
            }

        }

        console.log(chessBoard);

I'm having trouble to get the string on a new line once 8 characters have been used on that line. This is the part of the program i'm trying to figure out:

lineBreakCount++;

        if (lineBreakCount === chessBoardSize) {
            chessBoard += "\n";
            lineBreakCount = 0;
        }

When i run the code, i get back this:

 # # # #

But, it should be this:

 # # # #
# # # # 
 # # # #
# # # # 
 # # # #
# # # # 
 # # # #
# # # #