No need for the additional for loops:

function StairCase(n) { var s = ''; for (var i = 1; i <= n; i++) { s += ' '.repeat(n - i) + '#'.repeat(i) + '\n'; } return s; } 

If you don't have repeat for some reason, another implementation could be:

function Repeat(text, count) { var ret = ''; for(var i = 0; i < count; i++){ ret += text; } return ret; } function StairCase(n) { var s = ''; for (var i = 1; i <= n; i++) { s += Repeat(' ', n - i) + Repeat('#', i) + '\n'; }   return s; } 

No need for the additional for loops:

function StairCase(n) { var s = ''; for (var i = 1; i <= n; i++) { s += ' '.repeat(n - i) + '#'.repeat(i) + '\n'; } return s; } 

If you don't have repeat for some reason, another implementation could be:

String.prototype.Repeat = function(count) { var ret = ''; for(var i = 0; i < count; i++){ ret += this.valueOf(); } return ret; } function StairCase(n) { var s = ''; for (var i = 1; i <= n; i++) { s += ' '.Repeat(n - i) + '#'.Repeat(i) + '\n'; } return s; }