用js打印*號等腰三角形

let readline = require("readline-sync");

console.log("請輸入行數：");

let rows = ~~readline.question('')

let str = "";

let star = "";

for (let i = 1; i <= rows; i++) {

let str = "";

for (let k = 0; k < rows - i; k++) {

str += ` `;

}

for (let j = 1; j <= 2 * i - 1; j++) {

star += "*";

}

console.log(`${str}${star}`);

str = "";

star = "";

}