# Setting up a React Environment for ASP.NET MVC

Sung M. Kim Originally published at slightedgecoder.com on ・5 min read

Photo by Zoltan Tasi on Unsplash

I had a chance to update a legacy ASP.NET MVC website using AngularJS (yes, the first version) to use Webpack & Babel 7 (which used to import AngularJS files using script tags).

Previous post Setting up an ES6 Environment for ASP.NET MVC 5 was a bit outdated as it was using older version of babel and webpack, so I decided write more concise post to get started with the newest libraries.

As I have moved onto React, I will show you how to set up React environment for ASP.NET MVC 5.

## 🧐 Prerequisite

I will assume that you are familiar with NPM & Webpack,

so I won’t go into too much details on what each option in NPM & Webpack.

## 👣 Setup Steps

1. Create an ASP.NET MVC web site
2. Create & configure NPM configuration file (package.json)
3. Create & configure Babel configuration file (.babelrc)
4. Create & configure Webpack configuration file (webpack.config.js)
5. Install NPM packages
6. Install Visual Studio Extensions (NPM Task Runner)

#### 1. Create an ASP.NET MVC web site

Create a new ASP.NET MVC project (choose a choice of your .NET framework).

And select a template.

#### 2. Create & configure NPM configuration file (package.json)

Add a new item in the project root.

Create NPM configuration file, package.json.

And add a script section. And package.json would initially look like the following.

#### 3. Create & configure Babel configuration file (.babelrc)

Add a new file named .babelrc in the same directory as package.json file created in the previous step.

#### 4. Create & configure Webpack configuration file (webpack.config.js)

Create a file named webpack.config.js in the project root (same location as package.json & .babelrc) & configure it as shown below.

Webpack outputs a bundle as ./Scripts/dist/Home/react/bundle.js so let’s add the script in View\Home\Index.cshtml razor file.

#### 5. Install NPM packages

Now let’s install NPM packages to enable latest JavaScript and React syntax.

#### 6. Install Visual Studio Extensions (NPM Task Runner)

This is an optional step but to make our lives easier, let’s install a Visual Studio extension, NPM Task Runner for running NPM scripts from Visual Studio.

## ⚛ Let’s write some React code

Now we are ready to write a React script using the latest JavaScript syntax (ES6+).

Let’s add an entry point for React in Views\Home\Index.cshtml file by deleting everything except ViewBag.Title section and add <div id="app"></div>.

Now we have an entry point, let’s write a simple React file index.js under Scripts\Home\react directory.

## 🏃‍ Transpiling and Running

You could run the dev script within package.json file but let’s use the NPM task runner to make the life easier.

Open the “Task Runner Explorer” by right clicking on package.json file in the project root.

Start dev script (double click), which monitors the changes in index.js.

To enable browser-sync, you need copy a script generated by browser-sync message in _Layout.cshtml under Shared folder near end of </body> tag.

And lastly, let’s run ASP.NET from Visual Studio to see the result.

You’ve installed browser-sync* packages so as you change your code, the browser will reload automatically upon saving.

## 👋 Parting Words

In this post I’ve assumed that you know the basics of NPM & Webpack so skipped much of details so that you can easily get up and running.

Please refer to documentations linked in-line in the post if you want to understand how each step works and to troubleshoot should you run into an issue.

Source code is available on GitHub.

The post Setting up a React Environment for ASP.NET MVC appeared first on Sung's Technical Blog.

Posted on Oct 13 '18 by:

### Sung M. Kim

Exploring the world of TypeScript, React & Node

### Discussion

I start dev script in the task runner and it works very good, but only once. When I edit index.js and save it, it doens't recompile the file and I need to run dev again every time. Do you think I'am doing some thing worng?

Justo solved by adding the following lines in the webpack.config.js file:

watchOptions: {
poll: 1000 // Check for changes every second
}

Thanks for the update & the fix, Daniel~

I honestly moved away from using React within ASP.NET MVC, so wasn't aware of how to deal with it :)

Out of curiosity, have you moved away from using React with .NET MVC for a particular reason or have you just become interested in other things? My team wants to implement a JavaScript technology to build out some parts of our site that might be a pain otherwise and I have been learning React because it seemed like a good fit. I know everything is dependent on the project at hand, but if there are general drawbacks in your opinion I would be interested in hearing. Thanks for this article it was very useful!

Hi Tory, check out the replies below.

have you moved away from using React with .NET MVC for a particular reason or have you just become interested in other things?

Tooling support for classic ASP.NET MVC (I haven't used ASP.NET Core) has been subpar (hot reloading was buggy, requireing manual refresh & new JavaScript syntax was flagged as erroneous, etc).

And also following JamStack, having a separate API server with a pure React front-end helped to separate responsibilities.

I can't seem to find the post(was it a forum?) now, but MS wasn't focusing on making SPA easier to develop few years ago so I moved away.

Thanks for your perspective on this. Hoping to make the switch to .NET Core sometime soon and it seems like it is better suited, going to the Live 360 conference later this month and will hopefully get more information. Have a good one!

Hi, I tried out your process using VS2019, step by step and got the following error. Was hoping you might nudge me in the right direction :). [I am a relative newbie with npm]

ERROR in ./Scripts/Home/react/index.js
SyntaxError: d:\Docs\Scratch\ReactTest\Web\Scripts\Home\react\index.js: Unexpected token (5:4)

3 |
4 | const App = () => (
> 5 |     <>
|     ^
6 |         <h1>React in ASP.NET MVC!</h1>
7 |         <div>Hello React World</div>
8 |     </>
at Parser.raise (d:\Docs\Scratch\ReactTest\Web\node_modules\@babel\parser\lib\index.js:6400:17)
...


Hi Bill.

I am sorry it's because the code snippet is out of sync from the instruction. You might want to use React.Fragment instead of <>...</> because it's a syntatic sugar (you'd need to set up plugin-transform-react-jsx for that syntax to work, which is not set up in this article.)

As a workaround, you can use React.Fragment directly as shown below (I've also updated the gist to reflect the change).

import React from 'react';
import { render } from 'react-dom';

const App = () => (
<React.Fragment>
<h1>React in ASP.NET MVC!</h1>
<div>Hello React World</div>
</React.Fragment>
);

render(<App />, document.getElementById('app'));


Thanks so much for the quick reply.
That didn't change the outcome. Same error unexpected token.

I did note that the first line in the index.js file

import React from 'react';


was reporting an Intellisense error: "(js) cannot use imports, exports, or module augmentations when '--module' is 'none'"
Could this be a contributing factor.

Generally I prefer a watching build and manual refresh to browser sync. The number of times I want to lose track of an active debug state on the client as I type in an IDE are few. I've also experienced issues with synchronization and blocked calls regularly, as well as build issues that I catch much sooner if I can see the build output.

The last point is why I generally don't even bother with ide integration and just have a terminal session open persistently to run/monitor the updating build.

I've also experienced issues with synchronization and blocked calls regularly, as well as build issues that I catch much sooner if I can see the build output.

...

I generally don't even bother with ide integration

I can empathize with your experience because
I've also been bitten badly trying to figure out why a page wasn't working properly as I assumed the site was rendered correctly without any build issues.

That's why I have a separate build script that'd just run webpack without watching the file change so I can fire up an one off build when I am paranoid 😀😄

I tried to create about.js for about.cshtml and followed the same steps for index.js and index.cshtml, but it did not work. So I am not thinking if there are additional steps that I need to do? Thanks in advanced!

What's error and do you have code snippets handy?

So basically I just did the same things what you taught to about.js and about.cshtml, but it seems there is no thing to show up on the About Page

any idea how to create production verion (without node_modules folder) using the environment you created (mvc project)

When you generate a bundled JavaScript, you do not need to deploy the node_modules folder or add to the source control.

You could just deploy the bundled JavaScript in your production.

Or do you not want to have node_modules folder in the first place? If so you would need to use CDN scripts.

if i remove the "node_modules" from the environment , the project fall and i get error like Module build failed: Error: ENOENT: no such file or directory, open
'...node_modules\react\index.js'

Ah, I see what you mean.

I am sorry I made a mistake in the post so updated step 5. Install NPM packages to install react & react-dom as a dependency not as a dev dependency, which is not included in the final bundle.

So react & react-dom should be under dependencies as shown in package.json below.

{
"version": "1.0.0",
"name": "asp.net",
"private": true,
"scripts": {
"dev": "webpack --mode development --watch",
"build": "webpack"
},
"dependencies": {
"react": "^16.5.2",
"react-dom": "^16.5.2"
},
"devDependencies": {
"@babel/cli": "^7.1.2",
"@babel/core": "^7.1.2",
"@babel/plugin-proposal-class-properties": "^7.1.0",
"@babel/preset-env": "^7.1.0",
"@babel/preset-react": "^7.0.0",
"browser-sync": "^2.26.3",
"browser-sync-webpack-plugin": "^2.2.2",
"webpack": "^4.20.2",
"webpack-cli": "^3.1.2",
"webpack-notifier": "^1.7.0"
}
}


dont have any pack in devdependency

here is package.json

"name": "webbuildingoverhaul",
"version": "1.0.0",
"description": "",
"main": "webpack.config.js",
"dependencies": {
"@progress/kendo-data-query": "1.5.0",
"@progress/kendo-date-math": "1.3.2",
"@progress/kendo-drawing": "1.5.7",
"@progress/kendo-react-common": "2.4.0",
"@progress/kendo-react-dateinputs": "2.4.0",
"@progress/kendo-react-dropdowns": "2.4.0",
"@progress/kendo-react-excel-export": "2.6.1",
"@progress/kendo-react-grid": "2.4.0",
"@progress/kendo-react-inputs": "2.4.0",
"@progress/kendo-react-intl": "2.4.0",
"@progress/kendo-react-pdf": "2.4.0",
"@progress/kendo-theme-default": "2.56.0",
"babel-core": "6.26.3",
"babel-preset-es2015": "6.24.1",
"babel-preset-react": "6.24.1",
"bootstrap": "4.1.3",
"kendo-ui-core": "2018.3.911",
"moment": "2.22.2",
"prop-types": "15.6.2",
"react": "16.5.0",
"react-datetime": "2.16.3",
"react-dom": "16.5.0",
"react-redux": "5.0.7",
"react-router": "4.3.1",
"react-router-dom": "4.3.1",
"react-router-native": "4.3.0",
"react-transition-group": "2.4.0",
"redux": "3.7.2",
"redux-thunk": "2.3.0",
"restore": "0.3.0",
"webpack": "3.12.0",
"webpack-cli": "2.1.5",
"html-webpack-plugin": "3.1.0",
"webpack-dev-server": "3.1.8"
},
"devDependencies": {},
"scripts": {
"watch-test": "mocha --watch --reporter spec test",
"build-js": " reactify app.jsx | uglifyjs -mc > bundle.js",
"build": " webpack"
},
"author": "",
}

First off, thank you for the great article : it's helping me a lot to configure ReactJS.NET within our ASP.NET MVC 4 website.
In step 4, you wrote :
Webpack outputs a bundle as ./Scripts/dist/Home/react/index.js
when I think you meant :
Webpack outputs a bundle as ./Scripts/dist/Home/react/bundle.js
Cheers!

Thank you, Jérôme 🙏 enjoying the post and spotting the error.

I've updated the post 🙂🤜

Thanks for your tutorial! I now have a non-trivial React app in an ASP.NET MVC 5 project.

But now I need to be able debug the React app from VSCode/Chrome.

My webpack entrypoint is ./Scripts/react/index.jsx. The output is ./Scripts/dist/react/bundle.js. What should be my "webRoot" and "sourceMapPathOverrides" values in .vscode/launch.json? Am I missing other values?

  {
"version": "0.2.0",
"configurations": [
{
"name": "Chrome",
"type": "chrome",
"request": "launch",
"url": "http://localhost:23042",
"webRoot": "${workspaceFolder}/Scripts/react", "sourceMapPathOverrides": { "webpack:///Scripts/react/*": "${webRoot}/*"
}
}
]
}



You're welcome Nicolas.

But also consider creating React & Back-end in separate projects as discussed in this reddit post, Reaact and backend different or in same solution.

Thanks for the nice simple article.

Thanks Mark :)

Thanks a lot! That was really easy to follow!

You're welcome and thank you for the props, Riadul~

Great write up! That's a lot more to that than just running "create-react-app" so I appreciate your time figuring this out and writing it up (with screenshots!) so concisely!

Thanks Joe 😀.

Nice article and help me a lot

You can't imagine how much I thank you for this post. Thank you so much!!

That was a nice article but can you add some rules before moving to production with this setup.

Thank you very much for the article.
Should I include in the project all the node_modules folder?

You're welcome, Daniel.

You shouldn't include node_modules/ normally. But do include package-lock.json (or yarn-lock.json, if you are using yarn) as a lock file provide a way for others to create the same package structure.

did not work lmao, vs2019 here. It wont show me the content of react in the web app, but shows the other content

Hi,

Great tutorial. However, I'm getting an ERR_SSL_PROTOCOL_ERROR where I add in the script for browsersync. Any ideas?

Thanks

Hi I am new To ReactJs, Can You let Me Know How To Do It On Microsoft ASP MVC, What Are All Thing Required. I Want To Do DataBase Project using SQL SERVER. If You Let Me Know As Soon As Possible, Will Be Appreciated.

Hi, @maheshytech .
This post shows how to set up React environment on ASP.NET MVC.
I am not sure where the database project fits with it as the database project on visual studio lets you create TSQL scripts.

If you want to know how to provide database data from sql server, then you'd want to expose the data via ASP.NET WEB Api and access it via fetch or axios from React. That's outside the scope of this post, and you'd want to search for how to set up ASP.NET Web API (not sure if you are dealing with .NET core or framework)