loops&arrays

function max(numbers) {
  var currentMax = numbers[0];
  for (var i=0; i <= numbers.length; i++) {
    if (numbers[i] > currentMax) {
       currentMax = numbers[i];
    }
  }
  return currentMax;
}


function min(numbers) {
  var currentMin = numbers[0];
  for (var i=0; i <= numbers.length; i++) {
    if (numbers[i] < currentMin) {
       currentMin = numbers[i];
    }
  }
  return currentMin;
}




/* From here down, you are not expected to 
   understand.... for now :)  
   
   
   Nothing to see here!
   
*/


// tests

function testFunctionWorks(fn, input, expected) {
  if (fn(input) === expected) {
    console.log('SUCCESS: `' + fn.name + '` works on `[' + input + ']`');
    return true;
  }
  else {
    console.log(
      'FAILURE: `' + fn.name + '([' + input + '])` should be ' + expected +
      ' but was ' + fn(input)
    );
    return false;
  }
}


(function runTests() {
  // we'll use the variables in our test cases
  var numList1 = [-5, 28, 98, -20013, 0.7878, 22, 115];
  var realMin1 = numList1[3];
  var realMax1 = numList1[6];
  var numList2 = [0, 1, 2, 3, 4];
  var realMin2 = numList2[0];
  var realMax2 = numList2[4];
  
  var testResults = [
    testFunctionWorks(max, numList1, realMax1),
    testFunctionWorks(max, numList2, realMax2),
    testFunctionWorks(min, numList1, realMin1),
    testFunctionWorks(min, numList2, realMin2),
  ];
  
  var numPassing = testResults.filter(function(result){ return result; }).length;
  console.log(numPassing + ' out of ' + testResults.length + ' tests passing.');
})();

loops&arrays2

function average(numbers) {
  var total = numbers[0];
  for (var i=1; i < numbers.length; i++) {
    total+= numbers[i];
  }
  return total/numbers.length;
}


// this is an alternative implementation
// that is a bit cleaner, but perhaps harder to 
// "grok" (https://en.wikipedia.org/wiki/Grok) than
// our implementation of `average` above. `reduce` is
// built-in JavaScript method on arrays (
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce),
// and its used to generate a single result from a list of items.
function averageAlt(numbers) {
    return numbers.reduce(function(a, b) {return a + b;})/numbers.length;
}




/* From here down, you are not expected to 
   understand.... for now :)  
   
   
   Nothing to see here!
   
*/


// tests

function testFunctionWorks(fn, input, expected) {
  if (fn(input) === expected) {
    console.log('SUCCESS: `' + fn.name + '` works on `[' + input + ']`');
    return true;
  }
  else {
    console.log(
      'FAILURE: `' + fn.name + '([' + input + '])` should be ' + expected +
      ' but was ' + fn(input)
    );
    return false;
  }
}

(function runTests() {
  var numList1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
  var correctAns1 = 5.5;
  var numList2 = [0, -1, 1];
  var correctAns2 = 0;
  
  var testResults = [
    testFunctionWorks(average, numList1, correctAns1),
    testFunctionWorks(average, numList2, correctAns2)
  ];
  var numPassing = testResults.filter(function(result){ return result; }).length;
  console.log(numPassing + ' out of ' + testResults.length + ' tests passing.')
})();

loops&arrays3

function fizzBuzz(countTo) {
  var result = [];
  for (var i=1; i <= countTo; i++) {
    if (i % 15 === 0) {
      result.push('fizzbuzz'); 
    }
    else if (i % 5 === 0) {
      result.push('buzz');
    }
    else if (i % 3 === 0) {
      result.push('fizz');
    }
    else {
      result.push(i);
    }
  }
  return result;
}



/* From here down, you are not expected to 
   understand.... for now :)  
   
   
   Nothing to see here!
   
*/


// tests
(function testFizzBuzz() {
  // we'll use the variables in our test cases
  var countTo = 16;
  var expected = [
    1, 2, 'fizz', 4, 'buzz', 'fizz', 7, 8, 'fizz',
    'buzz', 11, 'fizz', 13, 14, 'fizzbuzz', 16
  ];

  var actual = fizzBuzz(countTo) || [];
  
  if (
    expected.length === actual.length &&
    expected.every(function(item, index) {
      return actual[index] === item;}) ) {
    
      console.log('SUCCESS: fizzBuzz is working');
  }
  else {
    console.log('FAILURE: fizzBuzz is not working');
  }  
})();