BlazorViteDemo

An example .NET 8 Blazor Web project working with Vite build tooling

Getting Started

The .NET workflow with Vite is outstanding. It provides a much more modern and faster development experience than when using Webpack. If you're interested in how to set up a new .NET project with Blazor and Vite, please follow the steps below and use this repository as a reference.

Install NPM Packages

Run npm init -y to scaffold the default package.json at the root of the Web project.
npm install vite --save-dev
npm install vite-plugin-mkcert --save-dev
npm install sass@npm:sass-embedded@latest --save-dev

Note that this is currently using an NPM alias for 'sass', but Vite intends to support the 'sass-embedded' package directly in the future as it is much faster. See: vitejs/vite#6734
npm install bootstrap --save

Install .NET Packages

Run dotnet add package Vite.AspNetCore at the root of the Web project.

Creating Vite Config

Using your desired text editor (hint: you can use code . to open VS Code at the current directory), open the directory and create a vite.config.js file at the root of the Web project.

Save the following configuration into this newly created file:

import { defineConfig } from "vite";
import mkcert from "vite-plugin-mkcert";
import path from "path";

import { Vite } from "./appsettings.Development.json";

export default defineConfig({
    appType: "custom",
    root: "Client",
    plugins: [ mkcert() ],
    resolve: {
        alias: { "~": __dirname }
    },
    build: {
        manifest: true,
        emptyOutDir: true,
        outDir: path.join(__dirname, "wwwroot"),
        assetsDir: "",
        rollupOptions: {
            input: [ 
                path.join(__dirname, "Client", "scripts", "app.js"), 
                path.join(__dirname, "Client", "styles", "app.scss")
            ],
            output: {
                entryFileNames: "js/[name]-[hash].bundle.min.js",
                chunkFileNames: "js/[name]-[hash].chunk.min.js",
                assetFileNames: (info) => {
                    if (info.name) {

                        // If the file is a CSS file, save it to the "css" folder
                        if (/\.css$/.test(info.name)) {
                            return "css/[name]-[hash].bundle.min.[ext]";
                        }

                        // If the file is an image file, save it to the "img" folder
                        if (/\.(png|jpe?g|gif|svg|webp|avif)$/.test(info.name)) {
                            return "img/[name][extname]";
                        }

                        // If the file is any other type of file, save it to the "assets" folder 
                        return "assets/[name][extname]";
                    } else {

                        // If the file name is not specified, save it to the output directory
                        return "[name][extname]";
                    }
                },
                manualChunks: (id) => {
                    if (id.includes('node_modules')) {
                        return 'lib';
                    }
                }
            }
        }
    },
    server: {
        port: Vite.Server.Port,
        strictPort: true,
        hmr: {
            host: "localhost",
            clientPort: Vite.Server.Port
        }
    }
});

Add the following 'Vite' section to the appsettings.Development.json file, so that it looks like the below:

{
    "Logging": {
        "LogLevel": {
        "Default": "Information",
        "Microsoft.AspNetCore": "Warning"
        }
    },
    "Vite": {
        "Server": {
        "Enabled": true,
        "Port": 5173,
        "Https": true,
        "AutoRun": true
        }
    }
}

Create a new directory at the project root called 'Client' e.g. mkdir Client.
Inside there, create 3 more directories to be used as input for the Vite build: public, scripts and styles.
Lastly create an app.js file inside of Client/scripts/ and an app.scss file inside of Client/styles/ to be used for the Javascript and CSS respectively. Note that the 'public' directory will be used for static assets such as the favicon that need to be copied to the output with no compilation or build process applied.

Using Vite With .NET

We already installed the Vite.AspNetCore package earlier which does most of the heavy lifting, but there is a final piece of configuration needed for everything to work.

Add the following NPM scripts to the package.json file:

"start": "echo Starting the development server && vite",
"dev": "vite",
"build": "vite build --mode development",
"publish": "vite build --mode production"

Open the wwwroot directory and copy the contents of app.css into our new app.scss file.
Delete the default bootstrap folder and add the line @import "bootstrap/scss/bootstrap"; to the top of app.scss.
Copy the favicon.png to the Client/public/ directory.

Add the following to the top of the Program.cs file:

using Vite.AspNetCore;

//...omitted for brevity

// Add the Vite manifest integration.
builder.Services.AddViteServices();

Add the following to the bottom of the Program.cs file:

if (app.Environment.IsDevelopment())
{
    if (bool.Parse(builder.Configuration["Vite:Server:Enabled"] ?? string.Empty)) 
    {
        // Proxies requests for css and js to 
        // the Vite development server for HMR.
        app.UseViteDevelopmentServer(true);
    }
}

Finally, update the App.razor component to use the new script and style assets provided via Vite by placing the following within the <head> tags:

@using Vite.AspNetCore

@inject IWebHostEnvironment env
@inject IViteManifest manifest
@inject IViteDevServerStatus vite

//...omitted for brevity

@if (env.IsDevelopment() && vite.IsMiddlewareEnable)
{
    <script type="module" src="@@vite/client"></script>
    <script type="module" src="scripts/app.js" defer></script>

    /** Note that this .scss is correct as it's purely acting as a 'key' 
    to the real css file being held in the Vite server memory. **/
    <link rel="stylesheet" href="styles/app.scss" />
}
else 
{
    IViteChunk? js = manifest["scripts/app.js"];
    if (js is not null) 
    {
        <script type="module" src="@js.File" defer></script>

        if (js.Imports is not null) 
        {
            foreach (string import in js.Imports) 
            {
                if (manifest.ContainsKey(import) is false) continue;

                <script type="module" src="@manifest[import]!.File" defer></script>
            }
        }
    }

    IViteChunk? css = manifest["styles/app.scss"];
    if (css is not null)
    {
        <link rel="stylesheet" href="@css.File" />
    }
}