Recursion example

find.js

// find the element in the array

var find = function(list, assertion) {
  'use strict';
  var recur = function(seq) {
    var head = seq[0], tail = seq.slice(1);
    if ( seq.length === 0 ) return undefined;
    else if ( assertion(head) ) return head;
    else return recur(tail);
  };
  return recur(list);
};

var my_list = ['bob', 'jane', 'joey'];

console.log(find(my_list, function(element) {
  return ( element === 'ivan');
}));