i try to reverse a string by finding the lenght first, using for-loop and den loops throught the range from the lenght to zero and concat it with other variable in order to store it in a reverse order, but i always get undefined prefix to it.
code -
function reverse1(str) {
let len = 0;
for (let i in str) {
len += 1;
}
var r = "";
for (var i = len; i >= 0; i--) {
r += str[i];
}
return r;
}
console.log(reverse1("hello"));
output- undefinedolleh
How to get rid of this undefined keyword which get prefix in the reverse string
You Are assigning i in for loop with string length , it should be start from len-1
for (var i = len-1; i >= 0; i--)
const str = 'Hello World';
const reversed = str .split('').reverse().join('')
console.log(reversed); // dlroW olleH