Tutorial by Examples: st

To use typescript with react in a node project, you must first have a project directory initialized with npm. To initialize the directory with npm init Installing via npm or yarn You can install React using npm by doing the following: npm install --save react react-dom Facebook released its ow...

The simplest react component without a state and no properties can be written as: import * as React from 'react'; const Greeter = () => <span>Hello, World!</span> That component, however, can't access this.props since typescript can't tell if it is a react component. To access ...

SELECT 1 a, '' b from DUAL; AB1(null)

SELECT COALESCE(a, b, c, d, 5) FROM (SELECT NULL A, NULL b, NULL c, 4 d FROM DUAL); COALESCE(A,B,C,D,5)4 In some case, using COALESCE with two parameters can be faster than using NVL when the second parameter is not a constant. NVL will always evaluate both parameters. COALESCE will stop a...

To navigate to a newest page, we can use the Navigate() method from the frame. contentRoot.Navigate(typeof(MyPage), parameter); where contentRoot is the Frame instance and MyPage a control inheriting from Page In MyPage, the OnNavigatedTo() method will be called once the navigation will complet...

A function that extends the functionality of the array by creating an object oriented remove function. // Need to restrict the extension to elements that can be compared. // The `Element` is the generics name defined by Array for its item types. // This restriction also gives us access to `index(...

Detailed instructions on getting c++-cli set up or installed.

A good way to visualize a 2d array is as a list of lists. Something like this: lst=[[1,2,3],[4,5,6],[7,8,9]] here the outer list lst has three things in it. each of those things is another list: The first one is: [1,2,3], the second one is: [4,5,6] and the third one is: [7,8,9]. You can access ...

The data in the pair can be accessed with utility functions. To access the car, we have to use the car function. (car (cons a b)) > a Also we can verify the following equality: (eq? a (car (cons a b))) > #t

To access the cdr, we have to use the cdr function. (cdr (cons a b)) b Also we can verify the following equality: (eq? b (cdr (cons a b))) #t

List in scheme are nothing else than a series of pairs nested in each other in the cdr of a cons. And the last cdr of a proper list is the empty list '(). To create the list (1 2 3 4), we'd have something like this: (cons 4 '()) > (4) (cons 3 (cons 4 '())) > (3 4) (cons 2 (cons 3 (cons 4...

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private bool navigateFlag = false; protected async override void OnNavigatingFrom(NavigatingCancelEventArgs e) { base.OnNavigatingFrom(e); if (!navigateFlag) { e.Cancel = true; var dialog = new MessageDialog("Navigate away?", Confir,); ...

NSMutableAttributedString * string = [[NSMutableAttributedString alloc] initWithString:@"firstsecondthird"]; [string addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(0,5)]; [string addAttribute:NSForegroundColorAttributeName value:[UIColor greenColo...

Firebase Cloud Messaging is the Firebase service that handles push notifications. You can add this service in any client: web, Android or IOS. The specific functioning for each must be read from the documentation. For adding FCM in any type of project, is always adding a library. Considering the s...

Let's say we have a form like the one below. We want to send the data to our webserver via AJAX and from there to a script running on an external server. So we have normal inputs, a multi-select field and a file dropzone where we can upload multiple files. Assuming the AJAX POST request was succ...

//Create a new ExcelPackage using (ExcelPackage excelPackage = new ExcelPackage()) { //Set some properties of the Excel document excelPackage.Workbook.Properties.Author = "VDWWD"; excelPackage.Workbook.Properties.Title = "Title of Document"; excelPackage.Workboo...

Session storage service : Common factory service that will save and return the saved session data based on the key. 'use strict'; /** * @ngdoc factory * @name app.factory:storageService * @description This function will communicate with HTML5 sessionStorage via Factory Service. */ a...

Maybe Maybe is an applicative functor containing a possibly-absent value. instance Applicative Maybe where pure = Just Just f <*> Just x = Just $ f x _ <*> _ = Nothing pure lifts the given value into Maybe by applying Just to it. The (<*>) function applies...

The first to thing to have: a model that contains a has_many relation with another model. class Project < ApplicationRecord has_many :todos end class Todo < ApplicationRecord belongs_to :project end In ProjectsController: class ProjectsController < ApplicationController d...