Category: JavaScript

cors-proxy-server – npm

I wanted to try out some Angular code against a demo odata service, but when requesting data from another domain in a web browser (the angular context) you might get:

Access to XMLHttpRequest at ‘http://services.odata.org/V4/OData/OData.svc/Products?$format=json’ from origin ‘http://localhost:4200’ has been blocked by CORS policy: Response to preflight request doesn’t pass access control check: Redirect is not allowed for a preflight request.

To get around this problem you could use a node proxy like this one:

Source: cors-proxy-server – npm

Install and start it up. Now we can call the odata service by prepending the proxy url before the actual api endpoint like this:
http://localhost:9090/http://services.odata.org/V4/OData/OData.svc/Products

Notice the double http://

The entire CORS problem can be summarized like this:

The web browser will prevent javascript to get a response from the service at domain x if that server does not explicitly say its ok to respond the remote caller. In our case our source domain is ‘localhost’ and the services.odata.org haven’t added that as a valid domain to respond to according to the web browser.

More info regarding CORS here: https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS

npm vs Yarn – Which Package Manager Should You Use? – KeyCDN

npm and Yarn are two well-known JavaScript package managers. If you’re not familiar with what a package manager does, it essentially is a way automate the process of installing, updating, configuring, and removing pieces of software (AKA packages) retrieved from a global registry. In this post, we’ll be going over what differences exist between two of the most popular JavaScript package managers – npm and Yarn.

Source: npm vs Yarn – Which Package Manager Should You Use? – KeyCDN

Different js scripts for different ASP.NET core environments· jonhilton.net – Making sense of .NET

When you reference a .js framework or library from your ASP.NET application, it makes sense to use the development version when you’re working on your own machine.

Referencing the development versions brings more useful error messages and integration with the React Developer tools.

But, you wouldn’t want to use these in production for performance reasons.

When you run the site in production, you’d want to reference the minified production versions of the React scripts.

Source: Different js scripts for different ASP.NET core environments· jonhilton.net – Making sense of .NET

Introducing Vue.js

Vue.js an up-and-coming JavaScript library used to build web-interfaces. In this article, we will introduce you to the library, by building a small, single-page sample application. We will discuss how, why and when to use Vue.js, and introduce you to its elementary features. As such you will learn about templating, and how to develop components and directives to build interactive, performant user interfaces.

Source: Introducing Vue.js | DotNetCurry

Also see: “VueJS vs Angular vs ReactJS with Demos”:
http://www.dotnetcurry.com/vuejs/1372/vuejs-vs-angular-reactjs-compare