Tutorial by Examples: l

As per the Mongoid Documentation, there are 16 valid field types: Array BigDecimal Boolean Date DateTime Float Hash Integer BSON::ObjectId BSON::Binary Range Regexp String Symbol Time TimeWithZone To add a field (let's call it name and have it be a String), add this to your mode...

Mongoid allows the classic ActiveRecord associations: One-to-one: has_one / belongs_to One-to-many: has_many / belongs_to Many-to-many: has_and_belongs_to_many To add an association (lets say the User has_many posts), you can add this to your User model file: has_many :posts and this to ...

Mongoid tries to have similar syntax to ActiveRecord when it can. It supports these calls (and many more) User.first #Gets first user from the database User.count #Gets the count of all users from the database User.find(params[:id]) #Returns the user with the id found in params[:id] User.w...

The first thing you need to know when structuring your apps is that the Meteor tool has some directories that are hard-coded with specific logic. At a very basic level, the following directories are "baked in" the Meteor bundler. client/ # client applicati...

Many people find themselves eventually supporting multiple applications, and desire to share code between apps. This leads to the concept of microservice architecture, and all-package apps. Essentially, the code from the entire classic directory structure is refactored out into packages. Even tho...

The most recent versions of Meteor ship with support for ecmascript, aka ES6 or ES2015. Instead of packages, Javascript now supports import statements and modules, which replaces the need for package-only applications. The latest directory structure is similar to the package-only structure, but us...

#include <iostream> #include <functional> using std::placeholders::_1; // to be used in std::bind example int stdf_foobar (int x, std::function<int(int)> moo) { return x + moo(x); // std::function moo called } int foo (int x) { return 2+x; } int foo_2 (int x, in...

While if performs an action only when its condition evaluate to true, if / else allows you to specify the different actions when the condition true and when the condition is false. Example: if (a > 1) puts("a is larger than 1"); else puts("a is not larger than 1"...

1) Create a Contract Class A contract class defines constants that help applications work with the content URIs, column names, intent actions, and other features of a content provider. Contract classes are not included automatically with a provider; the provider's developer has to define them and t...

globalize gem is a great solution to add translations to your ActiveRecord models. You can install it adding this to your Gemfile: gem 'globalize', '~> 5.0.0' If you're using Rails 5 you will also need to add activemodel-serializers-xml gem 'activemodel-serializers-xml' Model translations...

Like an HTTP request, an HTTP response may include additional headers to modify or augment the response it provides. A full list of available headers is defined in §6.2 of the specification. The most commonly-used headers are: Server, which functions like a User-Agent request header for the serv...

DELETE FROM `myTable` WHERE `someColumn` = 'something' The WHERE clause is optional but without it all rows are deleted.

A common problem is having a collection of items that all need to meet a certain criteria. In the example below we have collected two items for a diet plan and we want to check that the diet doesn't contain any unhealthy food. // First we create a collection $diet = collect([ ['name' => ...

You will often find yourself with a collection of data where you are only interested in parts of the data. In the example below we got a list of participants at an event and we want to provide a the tour guide with a simple list of names. // First we collect the participants $participants = colle...

Often you need to change the way a set of data is structured and manipulate certain values. In the example below we got a collection of books with an attached discount amount. But we much rather have a list of books with a price that's already discounted. $books = [ ['title' => 'The Pragma...

Collections also provide you with an easy way to do simple statistical calculations. $books = [ ['title' => 'The Pragmatic Programmer', 'price' => 20], ['title' => 'Continuous Delivery', 'price' => 30], ['title' => 'The Clean Coder', 'price' => 10], ] $min = col...

use-fixtures allows to wrap each deftest in namespace with code that runs before and after test. It can be used for fixtures or stubbing. Fixtures are just functions that take test function and run it with other necessary steps (before/after, wrap). (ns myapp.test (require [clojure.test :refer ...

Scala can be used as a scripting language. To demonstrate, create HelloWorld.scala with the following content: println("Hello") Execute it with the command-line interpreter (the $ is the command line prompt): $ scala HelloWorld.scala Hello If you omit .scala (such as if you simply...

A long-form syntax is available for defining multi-line functions. This can be useful when we use imperative structures such as loops. The expression in tail position is returned. For instance, the below function uses a for loop to compute the factorial of some integer n: function myfactorial(n) ...

In Vue.js, every component instance has its own isolated scope, which means that if a parent component has a child component - the child component has its own isolated scope and the parent component has its own isolated scope. For any medium to large size app, following best practices conventions p...