Solutions to JavaScript Under Pressure Game

script.js

// ======================================================
// Sample solutions to the exercises in the "JavaScript 
// Under Pressure" game. The game itself can be found 
// at this URL:
// http://toys.usvsth3m.com/javascript-under-pressure/
// 
// Felix Saparelli offered function-style variants of the 
// solutions, which can be found at this URL:
// https://gist.github.com/passcod/7639695
// ======================================================

// ======================================================
// Problem 1
// ======================================================
function doubleInteger(i) {
  // i will be an integer. Double it and return it.
            
  return i * 2;  
}

// ======================================================
// Problem 2
// ======================================================
function isNumberEven(i) {
    
  // i will be an integer. Return true if it's even, 
  // and false if it isn't.
  
  return i % 2 === 0;
}

// ======================================================
// Problem 3
// ======================================================
function getFileExtension(i) {
    
  // i will be a string, but it may not have a file extension.
  // return the file extension (with no period) if it has one, 
  // otherwise false
         
  var e = i.search(/\..+/)
  if (e !== -1) {
    return i.substr(e + 1);
  }
  else {
    return false;
  }
}

// Although above passes the test, 
// this is a much more reliable solution.
function getFileExtension(i) {
    var result = i.split('.');
    return result.length > 1 ? result.pop() : false;
}

// ======================================================
// Problem 4
// ======================================================
function longestString(i) {
    
    // i will be an array.
    // return the longest string in the array
        
    var longest = ''
    if (Array.isArray(i)) {      
      for (var n = 0, len = i.length; n < len; ++n) {
        if ((typeof i[n] === 'string') && 
            (i[n].length > longest.length)) {
          longest = i[n];
        }
      }
    }
  return longest;
}

// Alternate solution with some 
// functional programming thrown in.
function longestString(i) {
    var longest = '';
    if (Array.isArray(i)) {        
        var a = i.filter(function(t) {
            return typeof t === 'string';
        }).forEach(function(t) {
            if (t.length > longest.length) {
                longest = t;
            }
        });  
        
        return longest;
    }             
}

// ======================================================
// Problem 5
// ======================================================
function arraySum(i) {
    
  // i will be an array, containing integers, strings 
  // and/or arrays like itself. Sum all the integers you 
  // find, anywhere in the nest of arrays.
    
  var sum = 0;  
  if (Array.isArray(i)) {
    for (var n = 0, len = i.length; n < len; ++n) {
      if (Array.isArray(i[n])) {
        sum += arraySum(i[n]);
      }
      else if (typeof i[n] === 'number') {
        sum += i[n];
      }
    }
  }
  return sum;
}

Solutions-to-"JavaScript-Under-Pressure"-game.markdown

Solutions to "JavaScript Under Pressure" game

Sample solutions to the exercises in the "JavaScript Under Pressure" game. The game itself can be found at this URL: http://toys.usvsth3m.com/javascript-under-pressure/

A Pen by Zakir Tariverdiev on CodePen.

License.