javascript_practice/hw04/17_triangle.js

let str = '';
let strDots = '.';
let strHash = '#';
const rows = 6;

for (let i = 0; i < rows; i++) {
	str += `${strDots.repeat((rows - 1) - i)}${strHash.repeat(((rows * 2) - 1) - (((rows - 1) - i) * 2))}${strDots.repeat((rows - 1) - i)}\n`;
}
console.log(str);