accounting.js | lightweight JavaScript library for number , money | Runtime Evironment library

As already mentioned, IE11 doesn't support ES6. Looking at the line of code that throws that error you'll quickly find ES6 features (arrow functions for example).

Polyfilling will not provide you with the ability to use ES6, the only thing you can do is configure babel to target ES5 instead.

You can do that by editing your babelrc (for Babel 7):

You can do that in following steps:

• Add a same class to all the inputs you want to have this behavior. I added "test"
• You can use querySelectorAll to get all the input element with class="test"
• Then use forEach to loop through them and add event listeners to them
• Use this to access the element inside the function.

Here is the code.

You just shared the Gem file, but nothing how this app is developed, so it is insufficient information to give you an accurate response. But usually, two different methods are followed.

Two separate application, as your ruby on rails application working, can create another react application, and consume all endpoints present in your Ruby on Rails application, if you could not find some require endpoint, you can check already made endpoints and make few new one following the way. Hopefully, it would be easier to do.

In this method, you have to break apart your project and removing all Angular Gems already present in your project and start with fresh frontend with ReactJS. In my opinion, it requires much more Ruby on Rails knowledge to do it, but in the end, you will get just one project.

As from Gem file seem it is heavily using Angular, so probably you have run it and check if it has most of the Endpoints made Restful. If yes then I suggest to go on method one and create new ReactJS app, which will consume all endpoint made in Ruby on rails, that would be more work on React side app and less on Ruby on Rails. Even if you found that some endpoints are not present you can follow already created endpoints coding and action, where you will complete details. I understand there will be two different projects, but the learning curve to learn Ruby on Rails and integrating it with React would be more than having two different projects.

number: (val, alt = null) => (typeof val === 'number' ? val : val === undefined..... inside your bundle code says to me that arrow functions were not transpiled into normal functions. Try to add transform-es2015-arrow-functions babel plugin. If you will still experience similar errors - try to analyze the code of your bundle and find which ES6 feature not supported by IE11 remain there.

It's in the documentation. Either change the setting globally...

When using TypeScript, you have to install the types for the module, and the module itself. Preferably like this, so that the types will be added under devDependencies, since they're not used at runtime. Add the actual module to use it at runtime, add the types so that TypeScript can check it properly.

At first generate new pipe using angular-cli with command: ng g pipe format-number then:

You need to instead use the URL https://openexchangerates.org/api/latest.json

The error message cited in the question indicates that the openexchangerates.org server isn’t sending the Access-Control-Allow-Origin response header back to your code when your code makes a request to the URL http://openexchangerates.org/latest.json.

So it doesn’t matter what CORS config you do on your own server backend where your own code is being served from. The problem you ran into was only because of the openexchangerates.org not sending back that Access-Control-Allow-Origin response header.

But if you instead use the right URL—https://openexchangerates.org/api/latest.json—then that server will send back the Access-Control-Allow-Origin header in its response, and you won’t get that “CORS header ‘Access-Control-Allow-Origin' missing” error message any longer.