B Team Interview Questions.txt

How would I execute some code each element in a collection?
Loop in JS
each loop in Ruby

Convention over configuration:
Also know as coding by convention
decrease the number of decisions a developer has to make
Common in Ruby on Rails
Example - if there is a table called “sales” the database is also called “sales”

Rails naming conventions:
snake_case for local variables and instances methods
@sign for instance variables(“Hatted”) 
CONSTANTS in capitals
$sign in front of global variables 
camelCase for class and module names
? predicate method, ! destructive method  
	
When should load be used in Ruby as apposed to require?
You use load to execute code, and you use  require to import libraries.

What are the looping structures in Ruby?
.each
for
while
until

Why use validation?
Validations are used to ensure that only valid data is saved into your database.
Callbacks are methods that get called at certain moments of an object's life cycle. With callbacks it is possible to write code that will run whenever an Active Record object is created, saved, updated, deleted, validated, or loaded from the database.
Observers are similar to callbacks, but with important differences. Whereas callbacks can pollute a model with code that isn't directly related to its purpose, observers allow you to add the same functionality without changing the code of the model. 


What are helpers in Rails?
Used to extract complex logic out of the view so that you can organize your code better. Main two benefits are:
Extract some complexity out of the view
Make view logic easier to test
A lot of these are already provided by Ruby
How might your prevent name conflicts in Javascript?
You would best limit the scope to the appropriate files and the global scope. 
Use namespacing and global Identifiers
Closures


How would you model a coffee shop in Rails?
shop, staff, coffee, customers, suppliers	
staff belongs shop
shop has many coffees
shop has many suppliers
shop has many customers
customer has many coffees through shop


Why is it better to serve site assets for multiple domains?
The purpose is to multiple connections between the server and the browser
Most browsers allow a minimum of two simultaneous connections from a single host and modern browsers can take up to 60
large sites move their static content to CDN (content delivery network) which have geographically diverse servers 

What is FOUC? How do you avoid FOUC?
FOUC stands for a Flash of Unstyled Content. FOUC describes the instance when a website appears loaded without any styling. This occurs when the web browser renders a page before all of the information is retrieved.
The main method for prevention of FOUC is to hide all or part of a website until all of the css and javascript are loaded

What is the difference between classes and IDs in CSS?
Classes apply their styling to every html element that has been assigned with that class. Classes are prefixed with dots
IDs only apply their styling to the first element that has been assigned with that ID. IDs are prefixed with hashes.



What’s the difference between the variable: null, undefined and undeclared?
null variables exist and have null assigned to them
undefined: Something is undefined when it hasn’t been defined yet. If you call a variable or function without having actually created it yet the parser will give you a not defined error.
undeclared: A variable is undeclared when it does not use the var keyword. It gets created on the global object (that is, the window), it then operates in a different space as the declared variables.
undeclared variables don’t even exist
undefined variables exist, but don’t have anything assigned to them
null variables exist and have null assigned to them


What's a typical use case for anonymous functions?
Pass them as arguments in other functions, a.k.a callbacks
E.g. setInterval(callback, time)
Ajax requests
Closures

What does * { box-sizing: border-box; } do? What are its advantages?
All HTML elements can be considered as boxes. In CSS, the term "box model" is used when talking about design and layout.
The CSS box model is essentially a box that wraps around HTML elements, and it consists of: margins, borders, padding, and the actual content.
Important: When you set the width and height properties of an element with CSS, you just set the width and height of the content area. To calculate the full size of an element, you must also add the padding, borders and margins.
IE8 and earlier versions of IE, included padding and border in the width property.
To fix this problem, add a to the HTML page.
The box-sizing CSS property is used to alter the default CSS box model used to calculate widths and heights of elements. It is possible to use this property to emulate the behavior of browsers that do not correctly support the CSS box model specification.