为什么当我尝试重复指定次数的字符串时Javascript console.log结果为NaN

Question

function repeatS(srr, num) {
    if (num <= 0) {
        return "";
    }
    var result = "";
    for (var i = 0; i < num; i++) {
        result = +srr;
    }
    return result;
}
console.log(repeatS("ahfidhfd", 3));

strong text

Here is my question, the result is Nan, anyone knows what might be the problem here...

Answer 1

result = +srr;

应该

result += srr;

Answer 2

You use an unary plus + for converting a string to a number, but you need to assign the value to the left hand variable.

 function repeatS(srr, num) { if (num <= 0) { return ""; } var result = ""; for (var i = 0; i < num; i++) { result += srr; } return result; } console.log(repeatS("ahfidhfd", 3));