# Basic Algorithm Scripting - Repeat a String Repeat a String

Tell us what’s happening:
Describe your issue in detail here.

Hello! I understand the problem, but I just wanted to know what is wrong with my code? I’m I using “concat” in the wrong way?

``````function repeatStringNumTimes(str, num) {
let newStr = " ";
if ( num < 0) {
return str = " ";
} else {
for (let i = 0; i < num; i++) {
newStr.concat(str);
}
}
return newStr;

}

repeatStringNumTimes("abc", 3);
``````

User Agent is: `Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36`

Challenge: Basic Algorithm Scripting - Repeat a String Repeat a String

this is not an empty string, it is a string which contains space

What if `num` equals `0`. Instruction is `Return an empty string if num is not a positive number.`

Consider to read this, if you haven’t yet

Look at this part
`The concat() function concatenates the string arguments to the calling string and returns a new string. Changes to the original string or the returned string don't affect the other.`

``````function repeatStringNumTimes(str, num) {
let newStr = " ";
if ( num < 0) {
return str = " ";
} else {
for (let i = 0; i < num; i++) {
console.log(`i equals \${i} for current iteration`)
console.log(`newStr is \${newStr}`)
console.log(`length of newStr now is \${newStr.length}`)
newStr.concat(str);
}
}
console.log(newStr)
return newStr;

}

repeatStringNumTimes("abc", 3);
``````

we will see that newStr value is not changing as loop keeps going.

minor note: it is up to you - to use concat() or not, but it is worth mentioning, that some non-english versions of MDN article about `.concat()` recommend using `+` or `+=` operators instead when it is possible due to perfomance