woobianca / 08-2016-infinite-loops

Infinite Loops (Console-Driven-Development)

Git Workflow

Fork the Repository

1. On Github's website, navigate to the Infinite Loops Repository.
2. Click the "Fork" button near the top right part of the screen.
3. In the popup box, select your Github profile to copy the repository from the TelegraphPrep Github profile to your profile.

Clone the Repository

4. Once the repository is on your Github profile, navigate to your fork of that repository on Github's website.
5. Click the "Copy to clipboard" button to copy the Git link for the repository.
6. In your terminal, navigate to the folder you want to copy the repository into.
7. In your terminal, type git clone [pasteTheLinkYouJustCopiedHere] then hit enter to clone the repository from Github to your local machine.

Open the Repository on Your Local Machine

In your terminal, navigate to the repository. View the location of that repository in your finder by typing open . into the terminal.
To open the repository in Sublime, drag the repository folder over the Sublime icon in your Dock (at the bottom of the screen). All of the files within the repository should now be viewable in the sidebar in Sublime.

**More information on Git Workflow

Pair Programming Dynamics

See the following document on Pairing Dynamics Workflow

About the Sprint

Goals:

1. Expand understanding of how scope works when using functions within functions.
2. Practice passing anonymous functions as callback functions.

Lesson: Higher Order Functions

var loop = function(collection, callback){
    // ultimate side-effects function
    for (var i = 0; i < collection.length; i++){
      callback(collection[i]);
    }
};

countVowels:

countVowels takes one string as an argument and returns the number of vowels in the string.

• instead of writing your own for loop, use loop to complete countVowels.

// Example:
var numberOfVowels = countVowels('hey whats up');
console.log(numberOfVowels); // 4

stringReversal

stringReversal takes a string and returns it in reverse.

• use loop to complete stringReversal.

// Example:
    var olleh = stringReversal('hello');
    console.log(olleh) // 'olleh';
    

isPalindrome

A palindrome is a word that is spelled the exact same way forward than it is backward.isPalindrome takes one string as an argument and returns true if the string is a palindrome and false if the string is not a palindrome.

• use loop to complete isPalindrome.

// Example:
  var truePalindrome = isPalindrome('hannah');
  var falsePalindrome = isPalindrome('hello');
  

largestNumber

largestNumber takes one argument, an array of numbers, and returns the largest number in that array.

• use loop to complete largestNumber.

// Example:
  var nums = [1, 21, 471, 470, 39, 10, 92];
  var largestNum = largestNumber(nums);
  console.log(largestNum) // 471
  

multBy

multBy takes two arguments, an array and a number, and multiplies each value in the array by the input number.

• use loop to complete multBy.

  // Example:
  var nums = [1, 2, 3, 4, 5];
  var newArray = prep.multBy(nums, 3);
  console.log(newArray) // [3, 6, 9, 12, 15];
  

powerOf

powerOf takes two arguments, an array and a number, and raises each value in the array by the power of the input number.

• use loop to complete powerOf.

  // Example:
  var nums = [1, 2, 3, 4, 5];
  var newArray = prep.powerOf(nums, 3);
  console.log(newArray) // [1, 8, 27, 256, 3125];
  

capitalizeFirstLetters

capitalizeFirstLetters takes a string as an argument and returns the same string with all of the first letters capitalized.

• use loop to complete capitalizeFirstLetters

// Example:
  var string = 'hey how are you?';

  var newString = capitalizeFirstLetters(string)
  console.log(newString) // 'Hey How Are You?';
  

Expanding Loop to be used with objects:

Our current loop function only works with Arrays, and Objects are feeling left out. They have their own for-in loop that they'd like to stop using as well. Let's expand the purpose of our loop by adding in conditions that separate the functionality based on whether our input is an object or an array.

Remember the function we built during the week one self assessment? We can use it here as well:

var loop = function(collection, callback){

  if (Array.isArray(collection)){
    for (var i = 0; i < collection.length; i++){
      callback(collection[i]);
    }
  } else if (typeof collection === 'object'){
    for (var key in collection){
      callback(collection[key]);
    }
  }
};

By just adding 4 lines of code, we can loop through objects as well! Solve the next 2 challenges using our new and improved loop function.

collectValues

collectValues takes an object as an argument and returns an array containing all of its values.

// Example:

var obj = {name: 'Albrey', favoriteMovie: 'Inception'};

var listOfvalues = collectionValues(obj);

console.log(listOfValues) // ['Albrey', 'Inception'];

containsValue

containsValue takes two arguments, an object and a target value. If the object contains the target value, containsValue returns true; if not, containsValue returns false.

// Example:

var obj = {name: 'Albrey', favoriteMovie: 'Inception'};

var targetTest = containsValue(obj, 'Albrey');

console.log(targetTest) // true

Expanding our callback:

Okay, so we know now that we can run our loop function on an object or an array which is awesome, but we're still selling ourselves short here. You have probably noticed already -- the functions we have built are working with the values of both objects and arrays, but rarely (especially with objects), will that be the only data we care about.

For example, what if I wanted to collect data at only every even index. With a for-loop, that would look like this:

var evenIndexArray = function(arr){
  var results = [];
  // making sure our loop stops at the middle index in the array.
  for (var i = 0; i <= arr.length / 2; i++){
    // push each item
    result.push(arr[i]);
  };

  return results;
};

Attempting to use loop it would look like this:

var evenIndexArray = function(arr){
  var results = [];
  // we don't have access to the index, so we create a count to substitute
  var count = 0;
  loop(arr, function(val){
    // if the count is equal to zero, it's considered even.
    if (count === 0){
      result.push(val);
      // add 1 to the count
      count++
    // if the count is divisible by 2, it's even.
    } else if (count % 2 === 0){
      result.push(val);
      // add 1 to the count
      count++
    }
  });

  return results;
};

As you can see, that's a lot of extra functionality to add in! Our current loop function loses its advantage over the for loop because it hasn't been given access to the index corresponding with each value inside of our array. With a little bit of magic we change that.

Inside of our loop, let's pass an additional argument to our callback function: an index.

var loop = function(collection, func){

  if (Array.isArray(collection)){
    for (var i = 0; i < collection.length; i++){
      // passing the index as a second argument to our callback
      callback(collection[i], i);
    }
  } else if (typeof collection === 'object'){
    for (var key in collection){
      // passing the key as a second argument
      callback(collection[key], key);
    }
  }
};

Passing in the index/key allows any callback that we pass into loop access to the index/key corresponding to the current value that we're looping through! Pretty cool right? How would that change how we build evenIndexArray?

var evenIndexArray = function(arr){
  var results = [];
  // no need for count since we have access to the indexes;
  loop(arr, function(value, index){
    // accessing the index that's being passed as the second argument to our callback
    if (index === 0){
      results.push(value)
    } else if (index % 2 === 0){
      results.push(value);
    }
  });

  return results
};

Cool! So we got rid of the count all together, which makes this a much more efficient function. This also changes how we can interact with objects; we're rarely going to be worried just about the values. In the next handful of exercises you will need to access the value and the index/key in order to solve the prompts.

copyObj

copyObj takes one argument, an object, and returns a copy of that object.

• Use loop to create a copy of the input object.

    // Example:

    var obj = {name: 'Albrey', favoriteMovie: 'Inception'};

    var copyOfObj = copyObj(obj);

    console.log(copyOfObj) // {name: 'Albrey', favoriteMovie: 'Inception'};

extendObj

extendObj takes two objects as arguments and uses loop to extend obj1 with the contents of obj2

  // Example:

  var objOne = {name: 'Albrey', favoriteMovie: 'Inception'};
  var objTwo = {favoriteColor: 'Blue', hungry: true}

  extendObj(objOne, objTwo);

  console.log(objOne) // {name: 'Albrey', favoriteMovie: 'Inception', favoriteColor: 'Blue', hungry: true};

swapShuffle

swapShuffle takes one argument, an array, and mutates the array (it does not make a new one) and returns it with shuffled values.

  // Example:
    var numbers = [1, 2, 3, 4, 5];
    swapShuffle(numbers);
    console.log(numbers) //[3, 4, 2, 1, 5];

CarFax.com Sprint

My friend is looking to buy a car this month and is excited to search CarFax.com. Unfortunately their search form is broken, and he has employed you to fix it for him so he can get on the road as soon as possible. Use your loop function to solve the next set of prompts. We have created a list of cars sampleCarList that you should investigate before starting. Each car object has corresponding properties that you will need to sift through to get what you want. Good luck!

var sampleCarList = helpers.carFactory(helpers.carDatabase, helpers.carMaker, 100);
console.dir(sampleCarList);

findBlueCars

findBlueCars takes a carList array and returns an array containing each car object whose color is blue.

• create an array, allBlueCars, to store your cars in.
• use loop to loop through your carList array
• each car is an object, so you'll want to loop through the objects as well
• use a conditional to check whether the property is 'color', and the value is 'blue'
• if so, push your corresponding car to the allBlueCars array.
• when you're finished looping through, return the allBlueCars list.

findCarsByColor:

Let's expand our findBlueCars function to create an array of car objects whose color corresponds to what the user passes in.

• add a second parameter, color, to your findBlueCars function
• change your internal functionality to look for the color that the user specifies.

You'll notice that there aren't any directions for the next couple of exercises. We helped with the first 2 but it's your job to figure out how to build these out!

findCarsByYear:

findCarsByYear takes 2 parameters: carList and year and returns a collection of cars objects that were made in that year.

findCarsBetweenYears:

findCarsBetweenYears takes 3 parameters: carList, startYear, and endYear and returns a collection of cars objects that were made between those years.

findCarsByMake:

findCarsByMake takes 2 parameters: carList and make and returns a collection of car objects that have that make.

findCarsByMakeAndModel:

findCarsByMakeAndModel takes 3 parameters: carList, make, and model and returns a collection of car objects that have that make and model.

EXTRA CREDIT:

Random Price Generator

randomPriceGenerator extends each car object to have a 'price' property with the value set to a random number between 15000 and 50000.

// Example:
var carCollection = [{color: "black", make: "Ford", model:"Everest", year:1994}]
randomPriceGenerator(carCollection);
console.log(carCollection);

// [{color: "black", make: "Ford", model:"Everest", year:1994, price: 27847}];

Create another function, findByPrice that takes a price parameter and a list of cars and returns a list of every car that falls under that price. If no cars fall under the price return "there are no cars below the price you entered."

// Example:  
var carCollection = [{color: "black", make: "Ford", model:"Everest", year:1994, price: 27847}];
console.log(findByPrice(28000, carCollection);
// [{color: "black", make: "Ford", model:"Everest", year:1994, price: 27847}];

Extend your findByPrice function to take two parameters, a lowEndPrice and a highEndPrice and returns a list of cars that are between the two prices.

VerySpecificSearch

VerySpecificSearch allows the user to search using every specification: make, model, color, year, and between two prices. It returns a list containing each car that fulfills these VerySpecificSearch results. If there are no cars that fit the search terms, return "there are no cars that fit what you're looking for, try cars.com".

EXTRA EXTRA CREDIT:

If there aren't any cars that fit the search term return "there are no cars that fit what you're looking for" and redirect their browser to Cars.com.