Explanation of JS string reversal

string-reverse.js

var str = "hello world";

// Split on the empty character (between every
// letter).
var str_split = str.split('');            // => ['h', 'e', 'l', 'l', ' ', 'w', 'o', 'r', 'l', 'd']

// reverse the resulting array
var str_reverse = str_split.reverse();    // => ['d', 'l', 'r', 'o', 'w', ' ', 'l', 'l', 'e', 'h']

// join each string in the array, delimited by
// and empty string
var str_join = str_reverse.join('');      // => 'dlrow olleh';


/*
 * Since we can chain all of these together, we do not need to create variables
 * because that is just wasteful and the code is bulkier. So, we can simply do:
 */
str.split('').reverse().join('');



// And to add the function to the JavaScript String prototype
// (remember JS is not object-oriented, it's prototype-based)
// we do:
String.prototype.reverse = function() {
  return this.split('').reverse().join('');
}


// then we can do things like
var str_reversed = str.reverse();