##Assignments week 1:

Create a .js file that prints something to the console

Create a function that takes 3 arguments and returns the sum of the three arguments.

Write a program to answer the following questions:

* Can you store multiple types in an array? Numbers and strings?

* Can you compare inifities? (Not in Eyad's world) - does 6/0 == 10/0? How can you test this?

Create an object and a function that takes the object as a parameter and prints out all of its names and values.

On freecodecamp.com please try to do all [Basic JavaScript](https://www.freecodecamp.com/challenges/learn-how-free-code-camp-works) exercies (there are some topics we did not cover but you can do it). Please make sure you REALLY understand the exercies below:

1.

Create a function that takes two objects as parameters and compares them. You will actually need to write two functions - one that compares with == and one that compares with ===. Remember that objects can have objects inside of them so you'll need to find a way to compare every element of every object (types and values). For example:

in our example we'll say that obj1 == obj2 is true and obj1 === obj2 is false. Make sure you can see why before you write any code!

We saw that we can pass functions as arguments to other functions. Your task is to write a function that takes another function as an argument and runs it.

Write some code to test two arrays for equality using == and ===. Test the following:

var x = [1,2,3];

var y = [1,2,3];

var z = y;

What do you think will happen with x == y, x === y and z == y and z == x? Prove it!

Don't cheat! Seriously - try it first.

We did the following example in class:

Show that changing o2 changes o3 (or not) and changing o2 changes o3 (or not).

Does the order that you assign (o3 = o2 or o2 = o3) matter?

Have a look at https://javascriptweblog.wordpress.com/2010/09/27/the-secret-life-of-javascript-primitives/

'Coerce' means to try to change - so coercing `var x = '6'` to number means means trying to change the type to number temporarily.

1.

We learned a little bit about callbacks in JS. A callback is simply a function passed to another function that gets executed (run) after a potentially long running operation has completed. There is another function called `setTimeout` that will wait a specified period of time and then execute a function. For example:

```

function doIt() {

console.log('I am done');

}

setTimeout(doIt, 5000)

```

If you run the above code it will wait 5 seconds and print `I am done`. Please read something about setTimeout on MDN. The first argument to the `setTimeout` call is the callback (`doIt`)

You must write a function that takes 4 arguments.

- A start value

- An end value

- A callback to call if the number is divisible by 3

- A callback to use if the number is divisible by 5

The function should generate an array containing values from start value to end value (inclusive).

Then the function should itereate over the array and call the second argument if the array value is divisible by 3

The function should call the second argument if the array value is divisible by 5

Both functions should be called if the array value is divisible by both 3 and 5

```

THIS IS FAKE CODE

function threeFive(startIndex, stopIndex, threeCallback, fiveCallback) {

// make array

// start at beginning of array and check if you should call threeCallback or fiveCallback or go on to next

}

threeFive(10, 15, sayThree, sayFive);

// Should create an array [10,11,12,13,14,15]

// and call sayFive, sayThree, sayThree, sayFive - please make sure you see why these calls are made before you start coding

```

2.

Please solve this problem using:

1. A for loop

2. A while loop

3. A do loop

3.

Some practice with objects

4.

Nested loops

5.

We did some work with arrays - `var arr = [1,2,3]`

We can also nest arrays inside arrays like this `var arr2d = [[1,2], [3,4], [5,6]]` (for math people you can think of this as a matrix)

How would you print all the items of an array with 3 dimensions?

How about with K dimensions?

What if you didn't know how deep the array was nested? (You don't have to write code for this but think about it)

6.

Here are two functions that look like they do the something similar but they print different results. Please explain what's going on here.

If you are confused please run the code and then consult the Google for "javascript pass by value pass by reference"

7.

Next time we're going to cover the following Javascript topics:

- Immediately Invoked Function Execution (IIFE) and anonymous functions

- The this variable

- Scope and closures

- Promises (callbacks part 2)

- Using APIs

Please read up on these topics

Function call() - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/call

Function apply() - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/apply

Function bind() - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/bind

Arguments - https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Functions/arguments

A VERY popular StackOverflow article:

1.

Let's continue to learn a little more about scope and Closures.

Please solve the following three questions as a warm up to thinking about scope.

2.

What will be the output of the following code - and more importantly - WHY?

3.

Write a function that would allow you to do this:

4.

You will need to create an HTML document out of the below snippet to run the below code. A hint - the code is syntactically correct but doesn't do what you would expect. Can you see why and fix it?

Don't cheat - but if you get stuck ... http://stackoverflow.com/questions/750486/javascript-closure-inside-loops-simple-practical-example

Create a game!

* The game uses JSON as input

* The game should have user interaction

* Have at least 7 different functions

* Have at least one callback function

* Use objects (this can also be a source of inspiration for what kind of game to make)

* The game has to run on an HTML page (live on Github using pages.github.io using this tutorial https://pages.github.com/ and share your link on Trello)

* All the code needs to be commented

* The Github page should have a README.md describing how the game/code works and a whishlist of features to be added in the future

- Create at least 1 issue (bug / feature / code improvement) on another students github game repository. Do this in pairs.

- solve the issue proposed by another student in your github game repo. More info [here](https://hackyourfuture.slack.com/files/michahell/F31BX1XT6/Merging_a_local_branch_into_master)

- use a local non-tracking branch and merge into master

- or use a local tracking branch tracking your master, and push directly to master (slightly harder / more advanced)

[Example](https://www.w3schools.com/graphics/game_intro.asp) of a simple js game on w3schools