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, ...
First, install Mongoose with:
npm install mongoose
Then, add it to server.js as dependencies:
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
Next, create the database schema and the name of the collection:
var schemaName = new Schema({
request: String,
time: Nu...
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('...
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...
Protocols enable polymorphism in Elixir. Define protocols with defprotocol:
defprotocol Log do
def log(value, opts)
end
Implement a protocol with defimpl:
require Logger
# User and Post are custom structs
defimpl Log, for: User do
def log(user, _opts) do
Logger.info "User: ...
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...
We are not limited to destructuring an object/array, we can destructure a nested object/array.
Nested Object Destructuring
var obj = {
a: {
c: 1,
d: 3
},
b: 2
};
var {
a: {
c: x,
d: y
},
b: z
} = obj;
console.log(x, y, z); // 1,3,2
Nested Array ...
\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 ...
using System;
namespace TypeConversionApplication
{
class ExplicitConversion
{
static void Main(string[] args)
{
double d = 5673.74;
int i;
// cast double to int.
i = (int)d;
Console.WriteLine(i);
Cons...
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...
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', '...
