Tutorial by Examples: ed

Redux is very functional, so unit testing is very straightforward. Action creator: export function showSidebar () { return { type: 'SHOW_SIDEBAR' } } Action creators unit test: import expect from 'expect' import actions from './actions' import * as type from './constants' desc...

;Sends the keystroke for the letter "a" every 3 seconds. #Persistent SetTimer, SendLetterA, 3000 return SendLetterA() { Send, a }

This is an example of something that would have been straight up impossible with labels. If you execute the same label multiple times at the same time and they rely on variables that are being defined within them, they very likely interfere and cause unexpected behavior. Here is how to do it with f...

If we have this dictionary: set alpha {alice {items {}} bob {items {}} claudia {items {}} derek {items {}}} And want to add "fork" and "peanut" to Alice's items, this code won't work: dict lappend alpha alice items fork peanut dict get $alpha alice # => items {} items f...

The ASP.NET Core RTM release introduced BundlerMinifier.Core, a new Bundling and Minification tool that can be easily integrated into existing ASP.NET Core applications and doesn't require any external extensions or script files. Using BundlerMinifier.Core To use this tool, simply add a reference ...

Sometimes you may want to output something by one program and input it into another program, but can't use a standard pipe. ls -l | grep ".log" You could simply write to a temporary file: touch tempFile.txt ls -l > tempFile.txt grep ".log" < tempFile.txt This work...

While server side-code can run with elevated privileges, there is not an equivalent method to elevate privileges in client-side code (for obvious security reasons). As an alternative, you can specify credentials to emulate the access of a specific user or service account. To specify credentials, bu...

BAD CODE Dim f As System.Windows.Forms.Form f.ShowModal() GOOD CODE Dim f As System.Windows.Forms.Form = New System.Windows.Forms.Form ' Dim f As New System.Windows.Forms.Form ' alternative syntax f.ShowModal() EVEN BETTER CODE (Ensure proper disposal of IDisposable object more info) Us...

Ripple touch effect was introduced with material design in Android 5.0 (API level 21) and the animation is implemented by the new RippleDrawable class. Drawable that shows a ripple effect in response to state changes. The anchoring position of the ripple for a given state may be specified by call...

My.Computer.Network.DownloadFile("ftp://srv.my/myfile.txt", "donwload.txt", "Peter", "1234") This command download myfile.txt file from server named srv.my and saves it as donwload.txt into working directory. You can specify absolute path for downloaded fil...

My.Computer.Network.UploadFile("doc.txt", "ftp://server.my/on_server.txt", "Peter", "1234") This command upload doc.txt file from working directory (you could specify absolute path if you want) to server named server.my. File stored on the server will be na...

One potential implementation of Redis as a backend caching utility is the django-redis-cache package. This example assumes you already have a Redis server operating. $ pip install django-redis-cache Edit your settings.py to include a CACHES object (see Django documentation on caching). CACHES ...

One potential implementation of Redis as a backend caching utility is the django-redis package. This example assumes you already have a Redis server operating. $ pip install django-redis Edit your settings.py to include a CACHES object (see Django documentation on caching). CACHES = { 'de...

SimpleDateFormatter is great in a pinch, but like the name suggests it doesn't scale well. If you hard-code "MM/dd/yyyy" all over your application your international users won't be happy. Let Java do the work for you Use the static methods in DateFormat to retrieve the right formatting ...

def say_hi MESSAGE = "Hello" puts MESSAGE end The above code results in an error: SyntaxError: (irb):2: dynamic constant assignment.

C++17 namespace a { namespace b { template<class T> struct qualifies : std::false_type {}; } } namespace other { struct bob {}; } namespace a::b { template<> struct qualifies<::other::bob> : std::true_type {}; } You can enter both the a and b n...

Example: Invoke different constructors by passing relevant parameters import java.lang.reflect.*; class NewInstanceWithReflection{ public NewInstanceWithReflection(){ System.out.println("Default constructor"); } public NewInstanceWithReflection( String a){ ...

An important principle for unit testing is to separate data access from business logic. One efficient technique for this is to define interfaces for data access. Your main class always use a reference to that interface instead of direct reading or writing data. in production code the main class wil...

Sometimes you will make a mistake with a lengthy macro, but would rather edit it than re-record it entirely. You can do this using the following process: Put the macro on an empty line with "<register>p. If your macro is saved in register a, the command is "ap. Edit the ma...

When we use a condition within another condition we say the conditions are "nested". One special case of nested conditions is given by the elseif option, but there are numerous other ways to use nested conditons. Let's examine the following code: a = 2; if mod(a,2)==0 % MOD - modulo o...