js array reverse string code example
Example 1: javascript string reverse
"this is a test string".split("").reverse().join("");
//"gnirts tset a si siht"
// Or
const reverse = str => [...str].reverse().join('');
// Or
const reverse = str => str.split('').reduce((rev, char)=> `${char}${rev}`, '');
// Or
const reverse = str => (str === '') ? '' : `${reverse(str.substr(1))}${str.charAt(0)}`;
// Example
reverse('hello world'); // 'dlrow olleh'
Example 2: how to reverse a string in javascript without using reverse method
function reverseString(str) {
if (str === "") // This is the terminal case that will end the recursion
return "";
else
return reverseString(str.substr(1)) + str.charAt(0);
/*
First Part of the recursion method
You need to remember that you won’t have just one call, you’ll have several nested calls
Each call: str === "?" reverseString(str.subst(1)) + str.charAt(0)
1st call – reverseString("Hello") will return reverseString("ello") + "h"
2nd call – reverseString("ello") will return reverseString("llo") + "e"
3rd call – reverseString("llo") will return reverseString("lo") + "l"
4th call – reverseString("lo") will return reverseString("o") + "l"
5th call – reverseString("o") will return reverseString("") + "o"
Second part of the recursion method
The method hits the if condition and the most highly nested call returns immediately
5th call will return reverseString("") + "o" = "o"
4th call will return reverseString("o") + "l" = "o" + "l"
3rd call will return reverseString("lo") + "l" = "o" + "l" + "l"
2nd call will return reverserString("llo") + "e" = "o" + "l" + "l" + "e"
1st call will return reverserString("ello") + "h" = "o" + "l" + "l" + "e" + "h"
*/
}
reverseString("hello");