case1.js

(() => {

    const lineChars = ["x", " ", "o", " "];

    function createLine(length, isReverse){
        let result = "";
        for(let counter = 0; counter < length; counter++){
            if(isReverse){
                result = result + lineChars[counter % lineChars.length];
            }else{
                result = lineChars[counter % lineChars.length] + result;
            }
        }
        return result;
    }

    function buildShape(n){
        const max = n * 2 - 1;
        let result = "";
        for(let i = 1; i <= max; i++){
            if(i < n){
                result += "".padStart(n - 1) + createLine(i);
            }else if(i == n){
                result += createLine(n, true) + createLine(n - 1);
            }else{
                result += "".padStart(i - n) + createLine(n - (i - n) , true);
            }
            result += "\n";
        }
        return result;
    }


    (() => {
        console.log(buildShape(20));
    })();

})();