How to reverse a number/string in NodeJS?

Question

I have used this code to reverse a number but it is not working.

var buffer = new Buffer("<inputNumber>", "ucs2");
Array.prototype.reverse.call(new Unit16Array(buffer));
return buffer.toString("ucs2");

Where was I wrong? Is this approach right? Any other way of reversing a number/string without using buffer?

Answer 1

There are different ways to convert number to string :

String literal -> str = "" + num + "";
String constructor -> str = String(num);
toString -> str = num.toString();
String Literal simple -> str = "" + num;

The split() method is used to split a String object into an array of strings by separating the string into substrings.

Code : console.log('1000'.split(""));
Output : ["1", "0", "0", "0"]

The reverse() method is used to reverse an array in place. The first array element becomes the last and the last becomes the first.

Code : console.log(["1", "0", "0", "0"].reverse());
Output : ["0", "0", "0", "1"]

The join() method is used to join all elements of an array into a string.

Code : console.log(["1", "0", "0", "0"].reverse().join(""));
Output : "0001"

Answer 2

To reverse a number first you have to convert it into string. Convert that string into array. Reverse the array and join it to make a string then parse that string to number

var num = 1543;
var reverseNum = parseInt(a.toString().split("").reverse().join(""));
//Output : 3451

I hope this will help you.

Answer 3

Though the question is for numbers, it does also ask about strings, and was Google's first answer.

function reverse(value) {  
  return Array.from(
    String(value || '')
  ).reverse().join('')
}

Be careful of using string.split('') to split the given string into its characters. The String#split method doesn’t handle UTF-16 characters like emojis. The list of characters would then lose the emojis as individual characters. That’s the reason we recommend using Array.from() to create an array of characters from a given string.