#Static assets

Rsbuild supports importing static assets, including images, fonts, audio, and video.

#Asset formats

Rsbuild supports these formats by default:

• Images: png, jpg, jpeg, gif, svg, bmp, webp, ico, apng, avif, tif, tiff, jfif, pjpeg, pjp, cur.
• Fonts: woff, woff2, eot, ttf, otf, ttc.
• Audio: mp3, wav, flac, aac, m4a, opus.
• Video: mp4, webm, ogg, mov.

To import assets in other formats, refer to Extend Asset Types.

#Importing assets in JavaScript files

In JavaScript files, import static assets using relative paths:

// Import the logo.png image in the static directory
import logo from './static/logo.png';

console.log(logo); // "/static/logo.[hash].png"

export default () => <img src={logo} />;

Importing with alias is also supported:

import logo from '@/static/logo.png';

console.log(logo); // "/static/logo.[hash].png"

export default () => <img src={logo} />;

#URL assets

Rsbuild supports using JavaScript's native URL and import.meta.url to import static assets.

const logo = new URL('./static/logo.png', import.meta.url).href;

console.log(logo); // "/static/logo.[hash].png"

export default () => <img src={logo} />;

When using new URL() to reference .js or .ts files, they're treated as URL assets and aren't processed by Rsbuild's built-in SWC loader.

// foo.ts will remain the original content and be output to the dist directory
const fooTs = new URL('./foo.ts', import.meta.url).href;

console.log(fooTs); // "/static/foo.[hash].ts"

Similarly, when using new URL() to reference .css or .scss files, they're treated as URL assets and aren't processed by Rsbuild's built-in CSS loaders.

// foo.css will remain the original content and be output to the dist directory
const fooCss = new URL('./foo.css', import.meta.url).href;

console.log(fooCss); // "/static/foo.[hash].css"

#Importing assets in CSS files

In CSS files, you can reference static assets using relative paths:

.logo {
  background-image: url('../static/logo.png');
}

Importing with alias is also supported:

.logo {
  background-image: url('@/static/logo.png');
}

If you want to reference static assets using absolute paths in CSS files:

@font-face {
  font-family: DingTalk;
  src: url('/image/font/foo.ttf');
}

By default, Rsbuild's built-in css-loader will resolve absolute paths in url() and look for the specified modules. To skip resolving absolute paths, you can configure tools.cssLoader to filter out specific paths. Filtered paths will remain unchanged in the code.

export default {
  tools: {
    cssLoader: {
      url: {
        filter: (url) => {
          if (/\/image\/font/.test(url)) {
            return false;
          }
          return true;
        },
      },
    },
  },
};

#Inline assets

The result of importing static assets depends on the file size:

• If the file size is less than 4KiB, it will be converted to a base64 string and inlined in the code.
• If the file size is larger than 4KiB, a URL will be returned and the file will be emitted to the output directory.

import largeImage from './static/largeImage.png';
import smallImage from './static/smallImage.png';

console.log(largeImage); // "/static/largeImage.[hash].png"
console.log(smallImage); // "data:image/png;base64,iVBORw0KGgo..."

Adding the ?url query parameter ensures the asset is always loaded as a separate file and returns a URL:

import image from './static/image.png?url';

console.log(image); // "/static/image.[hash].png"

Adding the ?inline query parameter ensures the asset is always inlined in the code, regardless of file size:

import image from './static/image.png?inline';

console.log(image); // "data:image/png;base64,iVBORw0KGgo..."

For a more detailed introduction to asset inlining, refer to the Static Asset Inlining section.

#Importing as string

Rsbuild supports using the ?raw query parameter to import the raw content of static assets as a string in JavaScript.

import rawSvg from './static/logo.svg?raw';

console.log(rawSvg); // The raw content of the SVG file

Rsbuild also supports importing the raw content of JavaScript, TypeScript, and JSX files through the ?raw query parameter.

import rawJs from './script1.js?raw';
import rawTs from './script2.ts?raw';
import rawJsx from './script3.jsx?raw';
import rawTsx from './script4.tsx?raw';

console.log(rawJs); // The raw content of the JS file
console.log(rawTs); // The raw content of the TS file
console.log(rawJsx); // The raw content of the JSX file
console.log(rawTsx); // The raw content of the TSX file

You can also use the ?raw query parameter to import the raw content of CSS files, see CSS.

#Output files

When static assets are imported, they will be output to the dist directory. You can:

• Use output.filename to modify the output filename.
• Use output.distPath to modify the output path.

Read Output Files for details.

#URL prefix

The URL returned after importing an asset will automatically include the path prefix:

• In development, use dev.assetPrefix to set the path prefix.
• In production, use output.assetPrefix to set the path prefix.
• When either dev.assetPrefix or output.assetPrefix is not configured, the value of server.base will be automatically used as the default prefix.

For example, you can set output.assetPrefix to https://example.com:

export default {
  output: {
    assetPrefix: 'https://example.com',
  },
};

import logo from './static/logo.png';

console.log(logo); // "https://example.com/static/logo.[hash].png"

#Public folder

The public folder at the project root can be used to place static assets. These assets won't be built by Rsbuild and can be directly referenced via URL.

• When you start the dev server, these assets will be served under the server.base path (default /).
• When you perform a production build, these assets will be copied to the dist directory.

For example, you can place files such as robots.txt, manifest.json, or favicon.ico in the public folder.

#How to reference

You can reference files in the public directory via URL.

For example, in an HTML template, the ./public/favicon.ico file can be referenced as /favicon.ico. BASE_URL is the base path of the server.

<link rel="icon" href="<%= process.env.BASE_URL %>/favicon.ico" />

#Notes

Keep these points in mind when using the public folder:

• When referencing assets in the public folder via URL, use absolute paths instead of relative paths to ensure assets can be accessed correctly after deployment.

<!-- Wrong -->
<link rel="icon" href="../public/favicon.ico" />

<!-- Correct -->
<link rel="icon" href="/favicon.ico" />

• Avoid importing files from the public directory into your source code. The correct approach is to reference them by URL. You can place static assets that need to be imported into source code in the /src/assets directory.

// Wrong
import logo from '../public/logo.png';

// Correct
import logo from './assets/logo.png';

• During the production build, files in the public folder are copied to the output folder (default is dist). Be careful to avoid name conflicts with output files. When files in the public folder have the same name as outputs, the outputs have higher priority and will overwrite the conflicting public folder files. This feature can be disabled by setting server.publicDir.copyOnBuild to false.

#Custom behavior

Rsbuild provides the server.publicDir option which can be used to customize the name and behavior of the public folder, as well as to disable it.

export default {
  server: {
    publicDir: false,
  },
};

#Type declaration

When you import static assets in TypeScript code, TypeScript may prompt that the module is missing a type definition:

TS2307: Cannot find module './logo.png' or its corresponding type declarations.

To fix this, you need to add a type declaration file for the static assets, please create a src/env.d.ts file, and add the corresponding type declaration.

• Method 1: If the @rsbuild/core package is installed, you can reference the preset types provided by @rsbuild/core:

/// <reference types="@rsbuild/core/types" />

• Method 2: Manually add the required type declarations:

// Taking png images as an example
declare module '*.png' {
  const content: string;
  export default content;
}

After adding the type declaration, if the type error still exists, you can try to restart the current IDE, or adjust the directory where env.d.ts is located, making sure that TypeScript can correctly identify the type definition.

#Extend asset types

If the built-in asset types in Rsbuild cannot meet your requirements, you can extend additional static asset types in the following ways.

#Use source.assetsInclude

By using the source.assetsInclude config, you can specify additional file types to be treated as static assets.

export default {
  source: {
    assetsInclude: /\.pdf$/,
  },
};

After adding the above configuration, you can import *.pdf files in your code, for example:

import myFile from './static/myFile.pdf';

console.log(myFile); // "/static/myFile.[hash].pdf"

#Use tools.rspack

You can modify the built-in Rspack configuration and add custom static assets handling rules via tools.rspack.

For example, to treat *.pdf files as assets and output them to the dist directory, you can add the following configuration:

export default {
  tools: {
    rspack(config, { addRules }) {
      addRules([
        {
          test: /\.pdf$/,
          // converts asset to a separate file and exports the URL address.
          type: 'asset/resource',
        },
      ]);
    },
  },
};

For more information about asset modules, please refer to Rspack - Asset modules.

#Related configurations

Extended static asset types will be affected by the following configurations:

• output.filename.assets: Set the name of extended static assets.
• output.distPath.assets: Set the output directory of extended static assets.
• output.dataUriLimit.assets: Set the threshold of inlining for extended static assets.

#Custom rules

In some scenarios, you may need to bypass the built-in assets processing rules of Rsbuild and add some custom rules.

Taking PNG image as an example, you need to:

1. Modify the built-in Rspack config via tools.bundlerChain to exclude .png files using the exclude method.
2. Add custom asset processing rules via tools.rspack.

export default {
  tools: {
    bundlerChain(chain, { CHAIN_ID }) {
      chain.module
        // Use `CHAIN_ID.RULE.IMAGE` to locate the built-in image rule
        .rule(CHAIN_ID.RULE.IMAGE)
        .exclude.add(/\.png$/);
    },
    rspack(config, { addRules }) {
      addRules([
        {
          test: /\.png$/,
          // Add a custom loader to handle png images
          loader: 'custom-png-loader',
        },
      ]);
    },
  },
};

#Image format

When using image assets, you can choose an appropriate image format according to the pros and cons in the table below.