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Sung M. Kim
Sung M. Kim

Posted on • Originally published at slightedgecoder.com on

Setting up a React Environment for ASP.NET MVC

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Previous post Setting up an ES6 Environment for ASP.NET MVC 5 was a bit outdated as it was using older version of babel and webpack, so I decided write more concise post to get started with the newest libraries.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

Create a new ASP.NET MVC Project

And select a template.

MVC Template

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

Add a new item in the project root.

Add New Item…

Create NPM configuration file, package.json.

npm Configuration File

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.

And add following babel options.

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.

Bundle Script Tag

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.

NPM Task Runner Extension

⚛ 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.

index.js

🏃‍ 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.

Open Task Runner Explorer

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

Start “dev” script by double clicking on it

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.

Copy Browser-sync Script

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

Start ASP.NET MVC

♻ Reloading Browser Automatically

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

browser-sync at work

👋 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.

Top comments (46)

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daniel662 profile image
Daniel Freitas • Edited

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?

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daniel662 profile image
Daniel Freitas

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

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

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dance2die profile image
Sung M. Kim

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 :)

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vroland1 profile image
Tory Roland

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!

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dance2die profile image
Sung M. Kim

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.

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vroland1 profile image
Tory Roland

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!

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webatxcent profile image
Bill Butler

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
Module build failed (from ./node_modules/babel-loader/lib/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)
...
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dance2die profile image
Sung M. Kim • Edited

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'));
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webatxcent profile image
Bill Butler

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.

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technicallyty profile image
technicallyty

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

but then the picture below it shows it being added to _Layout.cshtml. Is this just a typo?

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jiaqizuo profile image
JiaqiZuo

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!

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dance2die profile image
Sung M. Kim

Hi @jiaqizuo

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

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jiaqizuo profile image
JiaqiZuo • Edited

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

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oudoulj profile image
Jérôme Oudoul

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!

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dance2die profile image
Sung M. Kim

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

I've updated the post 🙂🤜

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guymalka profile image
guymalka

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

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dance2die profile image
Sung M. Kim

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.

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guymalka profile image
guymalka • Edited

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'

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dance2die profile image
Sung M. Kim • Edited

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",
        "babel-loader": "^8.0.4",
        "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"
    }
}
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guymalka profile image
guymalka

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-loader": "7.1.5",
"babel-preset-es2015": "6.24.1",
"babel-preset-react": "6.24.1",
"bootstrap": "4.1.3",
"css-loader": "0.28.11",
"kendo-ui-core": "2018.3.911",
"moment": "2.22.2",
"prop-types": "15.6.2",
"react": "16.5.0",
"react-alert": "4.0.4",
"react-alert-template-basic": "1.0.0",
"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",
"style-loader": "0.19.1",
"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": "",
"license": "ISC"
}

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dance2die profile image
Sung M. Kim

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 😀😄

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riadhoq profile image
Riadul Hoque

Thanks a lot! That was really easy to follow!

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dance2die profile image
Sung M. Kim

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

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nicolasguzca profile image
Nick

Thank you so much for this article! I was looking to start with React in .Net.

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dance2die profile image
Sung M. Kim

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.

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nicolasguzca profile image
Nick

Great advice, thank you!

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markmbirira profile image
Mark Mbirira

Thanks for the nice simple article.

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dance2die profile image
Sung M. Kim

Thanks Mark :)

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