Tutorial by Examples: a

If you ever need an array that consists of extra arguments that you may or may not expect to have, apart from the ones you specifically declared, you can use the array rest parameter inside the arguments declaration as follows: Example 1, optional arguments into an array: function printArgs(arg1, ...

Setup First, install the necessary packages with: npm install express cors mongoose Code Then, add dependencies to your server.js file, create the database schema and the name of the collection, create an Express.js server, and connect to MongoDB: var express = require('express'); var cors =...

Setup First, install the necessary packages with: npm install express cors mongoose Code Then, add dependencies to server.js, create the database schema and the name of the collection, create an Express.js server, and connect to MongoDB: var express = require('express'); var cors = require('...

Adding a Fragment Statically File: activity_main.xml <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" > <fragment android:id=&qu...

There is currently a proposal (not yet part of the ECMAScript standard) to add a finally callback to promises that will be executed regardless of whether the promise is fulfilled or rejected. Semantically, this is similar to the finally clause of the try block. You would usually use this functional...

Use & to capture functions from other modules. You can use the captured functions directly as function parameters or within anonymous functions. Enum.map(list, fn(x) -> String.capitalize(x) end) Can be made more concise using &: Enum.map(list, &String.capitalize(&1)) Captu...

We often encounter a situation where a property we're trying to extract doesn't exist in the object/array, resulting in a TypeError (while destructuring nested objects) or being set to undefined. While destructuring we can set a default value, which it will fallback to, in case of it not being found...

\documentclass{article}% or book, report, ... \begin{document} See \cite{citeA} or \cite{citeB} or \cite{citeA, citeB}. \begin{thebibliography}{x} % \bibitem{<biblabel>} <citation> \bibitem{citeA} {\scshape Author, A}, {\itshape A title}, Journal of So-and-So, 2000....

round() tie breaking In Python 2, using round() on a number equally close to two integers will return the one furthest from 0. For example: Python 2.x2.7 round(1.5) # Out: 2.0 round(0.5) # Out: 1.0 round(-0.5) # Out: -1.0 round(-1.5) # Out: -2.0 In Python 3 however, round() will retur...

adduser command adds a user to the system. In order to add a new user type: sudo adduser <user_name> example: sudo adduser tom After typing the above command, you will be prompted to enter details about the new user, such as new password, user Full name, etc. Below is the information ...

An Interface's function known as a "contract" of functionality. It means that it declares properties and methods but it doesn't implement them. So unlike classes Interfaces: Can't be instantiated Can't have any functionality Can only contain methods * (Properties and Events are metho...

Don't you hate it when interfaces pollute you class with too many members you don't even care about? Well I got a solution! Explicit Implementations public interface IMessageService { void OnMessageRecieve(); void SendMessage(); string Result { get; set; } int Encoding { get; se...

Dictionary<TKey, TValue> is a map. For a given key there can be one value in the dictionary. using System.Collections.Generic; var people = new Dictionary<string, int> { { "John", 30 }, {"Mary", 35}, {"Jack", 40} }; // Reading data Console.Wri...

To register your device for push notifications, add the following code to your AppDelegate file in didFinishLaunchingWithOptions method: Swift func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool { // Override point for c...

Strict-Transport-Security: max-age=31536000; includeSubDomains Strict-Transport-Security is a promise to the browser that all future requests to this domain will be secure. For the future time period max-age: All outgoing HTTP requests from the browser will be converted to HTTPS on the client...

Strict-Transport-Security: max-age=31536000; includeSubDomains; preload HSTS is activated only after a successful HTTPS request to the server with a valid certificate. There is still a risk of a first-time user accessing the site, at which point a Man-in-the-Middle attack is possible. To make th...

Note: Before upgrading your Rails app, always make sure to save your code on a version control system, such as Git. To upgrade from Rails 4.2 to Rails 5.0, you must be using Ruby 2.2.2 or newer. After upgrading your Ruby version if required, go to your Gemfile and change the line: gem 'rails', '...

Basic Radios export class MyViewModel { favoriteColor = null; colors = ['Red', 'Yellow', 'Pink', 'Green', 'Purple', 'Orange', 'Blue']; } <template> <label repeat.for="color of colors"> <input type="radio" name="colors" value.bind=&q...

When using show.bind the element remains in the page and is either hidden or visible through the use of display:none or display:block behind the scenes. export class MyViewModel { isVisible = false; } <template> <div show.bind="isVisible"><strong>I can be b...

Unlike show.bind when using if.bind the element will be removed from the page if the supplied binding value is false or added into the page if the value is true. export class MyViewModel { isVisible = false; } <template> <div if.bind="isVisible"><strong>If ...