Javascript draw stairs by number

stairs.js

function draw(n) {
	var steps = new Array(n).fill('#');
  var len = steps.length;
  steps = steps.map((val, i) => {
  	return new Array(len - i - 1).fill(' ').join('') + val + new Array(i).fill('#').join('');
  });
  return steps.join('\n');
}

/*
  draw(6);
  
     #
    ##
   ###
  ####
 #####
######

*/