求大神js

(function () {
function triangle(nLines) {//获取杨辉三角数组
var aYHA = [], aLine, i, n;
while (nLines > 1) {
aLine = [];
aLine.push(1);
for (i = n = 1; i < nLines - 1; i++) {
aLine.push(n = (nLines - i) * n / i);
}
aLine.push(1);
aYHA.push(aLine);
nLines--;
}
aYHA.push([1]);
return aYHA;
}
function arr2Str(arr) {//将数组转化为字符串打印输出
var s = '';
return arr.map(function (e) {
return (s += '\t') + e.join('\t\t');
}).join('\n');
}
console.log(arr2Str(triangle(10)));
})();