webpack-contrib
html-loader
Exports HTML as string. HTML is minimized when the compiler demands.
Getting Started
To begin, you'll need to install html-loader:
npm install --save-dev html-loaderor
yarn add -D html-loaderor
pnpm add -D html-loaderThen add the plugin to your webpack config. For example:
file.js
import html from "./file.html";webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
},
],
},
};Options
sources
Type:
type sources =
| boolean
| {
list?: Array<{
tag?: string;
attribute?: string;
type?: string;
filter?: (
tag: string,
attribute: string,
attributes: string,
resourcePath: string,
) => boolean;
}>;
urlFilter?: (
attribute: string,
value: string,
resourcePath: string,
) => boolean;
scriptingEnabled?: boolean;
};Default: true
By default every loadable attribute (for example - <img src="image.png">) is imported (const img = require('./image.png') or new URL("./image.png", import.meta.url)).
You may need to specify loaders for images in your configuration (recommended asset modules).
Supported tags and attributes:
- the
srcattribute of theaudiotag - the
srcattribute of theembedtag - the
srcattribute of theimgtag - the
srcsetattribute of theimgtag - the
srcattribute of theinputtag - the
dataattribute of theobjecttag - the
srcattribute of thescripttag - the
hrefattribute of thescripttag - the
xlink:hrefattribute of thescripttag - the
srcattribute of thesourcetag - the
srcsetattribute of thesourcetag - the
srcattribute of thetracktag - the
posterattribute of thevideotag - the
srcattribute of thevideotag - the
xlink:hrefattribute of theimagetag - the
hrefattribute of theimagetag - the
xlink:hrefattribute of theusetag - the
hrefattribute of theusetag - the
hrefattribute of thelinktag when therelattribute containsstylesheet,icon,shortcut icon,mask-icon,apple-touch-icon,apple-touch-icon-precomposed,apple-touch-startup-image,manifest,prefetch,preloador when theitempropattribute isimage,logo,screenshot,thumbnailurl,contenturl,downloadurl,duringmedia,embedurl,installurl,layoutimage - the
imagesrcsetattribute of thelinktag when therelattribute containsstylesheet,icon,shortcut icon,mask-icon,apple-touch-icon,apple-touch-icon-precomposed,apple-touch-startup-image,manifest,prefetch,preload - the
contentattribute of themetatag when thenameattribute ismsapplication-tileimage,msapplication-square70x70logo,msapplication-square150x150logo,msapplication-wide310x150logo,msapplication-square310x310logo,msapplication-config,twitter:imageor when thepropertyattribute isog:image,og:image:url,og:image:secure_url,og:audio,og:audio:secure_url,og:video,og:video:secure_url,vk:imageor when theitempropattribute isimage,logo,screenshot,thumbnailurl,contenturl,downloadurl,duringmedia,embedurl,installurl,layoutimage - the
icon-urivalue component incontentattribute of themetatag when thenameattribute ismsapplication-task
boolean
The true value enables the processing of all default elements and attributes, the false value disables the processing of all attributes.
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
// Disables attributes processing
sources: false,
},
},
],
},
};object
Allows you to specify which tags and attributes to process, filter them, filter urls and process sources starting with /.
For example:
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
sources: {
list: [
// All default supported tags and attributes
"...",
{
tag: "img",
attribute: "data-src",
type: "src",
},
{
tag: "img",
attribute: "data-srcset",
type: "srcset",
},
],
urlFilter: (attribute, value, resourcePath) => {
// The `attribute` argument contains a name of the HTML attribute.
// The `value` argument contains a value of the HTML attribute.
// The `resourcePath` argument contains a path to the loaded HTML file.
if (/example\.pdf$/.test(value)) {
return false;
}
return true;
},
},
},
},
],
},
};list
Type:
type list = Array<{
tag?: string;
attribute?: string;
type?: string;
filter?: (
tag: string,
attribute: string,
attributes: string,
resourcePath: string,
) => boolean;
}>;Default: supported tags and attributes.
Allows to setup which tags and attributes to process and how, as well as the ability to filter some of them.
Using ... syntax allows you to extend default supported tags and attributes.
For example:
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
sources: {
list: [
// All default supported tags and attributes
"...",
{
tag: "img",
attribute: "data-src",
type: "src",
},
{
tag: "img",
attribute: "data-srcset",
type: "srcset",
},
{
// Tag name
tag: "link",
// Attribute name
attribute: "href",
// Type of processing, can be `src` or `scrset`
type: "src",
// Allow to filter some attributes
filter: (tag, attribute, attributes, resourcePath) => {
// The `tag` argument contains a name of the HTML tag.
// The `attribute` argument contains a name of the HTML attribute.
// The `attributes` argument contains all attributes of the tag.
// The `resourcePath` argument contains a path to the loaded HTML file.
if (/my-html\.html$/.test(resourcePath)) {
return false;
}
if (!/stylesheet/i.test(attributes.rel)) {
return false;
}
if (
attributes.type &&
attributes.type.trim().toLowerCase() !== "text/css"
) {
return false;
}
return true;
},
},
],
},
},
},
],
},
};If the tag name is not specified it will process all the tags.
You can use your custom filter to specify html elements to be processed.
For example:
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
sources: {
list: [
{
// Attribute name
attribute: "src",
// Type of processing, can be `src` or `scrset`
type: "src",
// Allow to filter some attributes (optional)
filter: (tag, attribute, attributes, resourcePath) => {
// The `tag` argument contains a name of the HTML tag.
// The `attribute` argument contains a name of the HTML attribute.
// The `attributes` argument contains all attributes of the tag.
// The `resourcePath` argument contains a path to the loaded HTML file.
// choose all HTML tags except img tag
return tag.toLowerCase() !== "img";
},
},
],
},
},
},
],
},
};Filter can also be used to extend the supported elements and attributes.
For example, filter can help process meta tags that reference assets:
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
sources: {
list: [
{
tag: "meta",
attribute: "content",
type: "src",
filter: (tag, attribute, attributes, resourcePath) => {
if (
attributes.value === "og:image" ||
attributes.name === "twitter:image"
) {
return true;
}
return false;
},
},
],
},
},
},
],
},
};[!NOTE]
source with a
tagoption takes precedence over source without.
Filter can be used to disable default sources.
For example:
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
sources: {
list: [
"...",
{
tag: "img",
attribute: "src",
type: "src",
filter: () => false,
},
],
},
},
},
],
},
};urlFilter
Type:
type urlFilter = (
attribute: string,
value: string,
resourcePath: string,
) => boolean;Default: undefined
Allow to filter urls. All filtered urls will not be resolved (left in the code as they were written).
Non-requestable sources (for example <img src="javascript:void(0)">) are not handled by default.
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
sources: {
urlFilter: (attribute, value, resourcePath) => {
// The `attribute` argument contains a name of the HTML attribute.
// The `value` argument contains a value of the HTML attribute.
// The `resourcePath` argument contains a path to the loaded HTML file.
if (/example\.pdf$/.test(value)) {
return false;
}
return true;
},
},
},
},
],
},
};scriptingEnabled
Type:
type scriptingEnabled = boolean;Default: true
By default, the parser in html-loader interprets content inside <noscript> tags as #text, so processing of content inside this tag will be ignored.
In order to enable processing inside <noscript> for content recognition by the parser as #AST, set this parameter to: false
Additional information: scriptingEnabled
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
sources: {
// Enables processing inside the <noscript> tag
scriptingEnabled: false,
},
},
},
],
},
};preprocessor
Type:
type preprocessor = (content: string, loaderContext: LoaderContext) => string;Default: undefined
Allows pre-processing of content before handling.
[!WARNING]
You should always return valid HTML
file.hbs
<div>
<p>{{firstname}} {{lastname}}</p>
<img src="image.png" alt="alt" />
<div>function
You can set the preprocessor option as a function instance.
webpack.config.js
const Handlebars = require("handlebars");
module.exports = {
module: {
rules: [
{
test: /\.hbs$/i,
loader: "html-loader",
options: {
preprocessor: (content, loaderContext) => {
let result;
try {
result = Handlebars.compile(content)({
firstname: "Value",
lastname: "OtherValue",
});
} catch (error) {
loaderContext.emitError(error);
return content;
}
return result;
},
},
},
],
},
};You can also set the preprocessor option as an asynchronous function instance.
For example:
webpack.config.js
const Handlebars = require("handlebars");
module.exports = {
module: {
rules: [
{
test: /\.hbs$/i,
loader: "html-loader",
options: {
preprocessor: async (content, loaderContext) => {
let result;
try {
result = await Handlebars.compile(content)({
firstname: "Value",
lastname: "OtherValue",
});
} catch (error) {
await loaderContext.emitError(error);
return content;
}
return result;
},
},
},
],
},
};postprocessor
Type:
type postprocessor = (content: string, loaderContext: LoaderContext) => string;Default: undefined
Allows post-processing of content after replacing all attributes (like src/srcset/etc).
file.html
<img src="image.png" />
<img src="<%= 'Hello ' + (1+1) %>" />
<img src="<%= require('./image.png') %>" />
<img src="<%= new URL('./image.png', import.meta.url) %>" />
<div><%= require('./gallery.html').default %></div>function
You can set the postprocessor option as a function instance.
webpack.config.js
const Handlebars = require("handlebars");
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
postprocessor: (content, loaderContext) => {
// When you environment supports template literals (using browserslist or options) we will generate code using them
const isTemplateLiteralSupported = content[0] === "`";
return content
.replace(/<%=/g, isTemplateLiteralSupported ? `\${` : '" +')
.replace(/%>/g, isTemplateLiteralSupported ? "}" : '+ "');
},
},
},
],
},
};You can also set the postprocessor option as an asynchronous function instance.
For example:
webpack.config.js
const Handlebars = require("handlebars");
module.exports = {
module: {
rules: [
{
test: /\.hbs$/i,
loader: "html-loader",
options: {
postprocessor: async (content, loaderContext) => {
const value = await getValue();
// When you environment supports template literals (using browserslist or options) we will generate code using them
const isTemplateLiteralSupported = content[0] === "`";
return content
.replace(/<%=/g, isTemplateLiteralSupported ? `\${` : '" +')
.replace(/%>/g, isTemplateLiteralSupported ? "}" : '+ "')
.replace("my-value", value);
},
},
},
],
},
};minimize
Type:
type minimize =
| boolean
| {
caseSensitive?: boolean;
collapseWhitespace?: boolean;
conservativeCollapse?: boolean;
keepClosingSlash?: boolean;
minifyCSS?: boolean;
minifyJS?: boolean;
removeComments?: boolean;
removeRedundantAttributes?: boolean;
removeScriptTypeAttributes?: boolean;
removeStyleLinkTypeAttributes?: boolean;
};Default: true in production mode, otherwise false
Tell html-loader to minimize HTML.
boolean
The enabled rules for minimizing by default are the following ones:
({
caseSensitive: true,
collapseWhitespace: true,
conservativeCollapse: true,
keepClosingSlash: true,
minifyCSS: true,
minifyJS: true,
removeComments: true,
removeRedundantAttributes: true,
removeScriptTypeAttributes: true,
removeStyleLinkTypeAttributes: true,
});webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
minimize: true,
},
},
],
},
};object
webpack.config.js
See html-minifier-terser's documentation for more information on the available options.
The default rules can be overridden using the following options in your webpack.conf.js
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
minimize: {
removeComments: false,
collapseWhitespace: false,
},
},
},
],
},
};The default rules can be extended:
webpack.config.js
const { defaultMinimizerOptions } = require("html-loader");
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
minimize: {
...defaultMinimizerOptions,
removeComments: false,
collapseWhitespace: false,
},
},
},
],
},
};esModule
Type:
type esModule = boolean;Default: true
By default, html-loader generates JS modules that use the ES modules syntax.
There are some cases in which using ES modules is beneficial, such as module concatenation and tree shaking.
You can enable a CommonJS modules syntax using:
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
esModule: false,
},
},
],
},
};Examples
Disable url resolving using the <!-- webpackIgnore: true --> comment
With <!-- webpackIgnore: true --> comment, one can disable sources handling for next tag.
<!-- Disabled url handling for the src attribute -->
<!-- webpackIgnore: true -->
<img src="image.png" />
<!-- Disabled url handling for the src and srcset attributes -->
<!-- webpackIgnore: true -->
<img
srcset="image.png 480w, image.png 768w"
src="image.png"
alt="Elva dressed as a fairy"
/>
<!-- Disabled url handling for the content attribute -->
<!-- webpackIgnore: true -->
<meta itemprop="image" content="./image.png" />
<!-- Disabled url handling for the href attribute -->
<!-- webpackIgnore: true -->
<link rel="icon" type="image/png" sizes="192x192" href="./image.png" />roots
With resolve.roots one can specify a list of directories where requests of server-relative URLs (starting with '/') are resolved.
webpack.config.js
module.exports = {
context: __dirname,
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {},
},
{
test: /\.jpg$/,
type: "asset/resource",
},
],
},
resolve: {
roots: [path.resolve(__dirname, "fixtures")],
},
};file.html
<img src="/image.jpg" />// => image.jpg in __dirname/fixtures will be resolvedCDN
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.jpg$/,
type: "asset/resource",
},
{
test: /\.png$/,
type: "asset/inline",
},
],
},
output: {
publicPath: "http://cdn.example.com/[fullhash]/",
},
};file.html
<img src="image.jpg" data-src="image2x.png" />index.js
require("html-loader!./file.html");
// => '<img src="http://cdn.example.com/49eba9f/a992ca.jpg" data-src="image2x.png">'require('html-loader?{"sources":{"list":[{"tag":"img","attribute":"data-src","type":"src"}]}}!./file.html');
// => '<img src="image.jpg" data-src="data:image/png;base64,..." >'require('html-loader?{"sources":{"list":[{"tag":"img","attribute":"src","type":"src"},{"tag":"img","attribute":"data-src","type":"src"}]}}!./file.html');
// => '<img src="http://cdn.example.com/49eba9f/a992ca.jpg" data-src="data:image/png;base64,..." >'Process script and link tags
script.file.js
console.log(document);style.file.css
a {
color: red;
}file.html
<!doctype html>
<html>
<head>
<meta charset="UTF-8" />
<title>Title of the document</title>
<link rel="stylesheet" type="text/css" href="./style.file.css" />
</head>
<body>
Content of the document......
<script src="./script.file.js"></script>
</body>
</html>webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.html$/,
type: "asset/resource",
generator: {
filename: "[name][ext]",
},
},
{
test: /\.html$/i,
use: ["html-loader"],
},
{
test: /\.js$/i,
exclude: /\.file.js$/i,
loader: "babel-loader",
},
{
test: /\.file.js$/i,
type: "asset/resource",
},
{
test: /\.css$/i,
exclude: /\.file.css$/i,
loader: "css-loader",
},
{
test: /\.file.css$/i,
type: "asset/resource",
},
],
},
};Templating
You can use any template system. Below is an example for handlebars.
file.hbs
<div>
<p>{{firstname}} {{lastname}}</p>
<img src="image.png" alt="alt" />
<div>webpack.config.js
const Handlebars = require("handlebars");
module.exports = {
module: {
rules: [
{
test: /\.hbs$/i,
loader: "html-loader",
options: {
preprocessor: (content, loaderContext) => {
let result;
try {
result = Handlebars.compile(content)({
firstname: "Value",
lastname: "OtherValue",
});
} catch (error) {
loaderContext.emitError(error);
return content;
}
return result;
},
},
},
],
},
};PostHTML
You can use PostHTML without any additional loaders.
file.html
<img src="image.jpg" />webpack.config.js
const posthtml = require("posthtml");
const posthtmlWebp = require("posthtml-webp");
module.exports = {
module: {
rules: [
{
test: /\.hbs$/i,
loader: "html-loader",
options: {
preprocessor: (content, loaderContext) => {
let result;
try {
result = posthtml().use(plugin).process(content, { sync: true });
} catch (error) {
loaderContext.emitError(error);
return content;
}
return result.html;
},
},
},
],
},
};Export into HTML files
A very common scenario is exporting the HTML into their own .html file, to serve them directly instead of injecting with javascript.
This can be achieved with a combination of html-loader and asset modules.
The html-loader will parse the URLs, require the images and everything you
expect. The extract loader will parse the javascript back into a proper html
file, ensuring images are required and point to proper path, and the asset modules
will write the .html file for you. Example:
webpack.config.js
module.exports = {
output: {
assetModuleFilename: "[name][ext]",
},
module: {
rules: [
{
test: /\.html$/,
type: "asset/resource",
generator: {
filename: "[name][ext]",
},
},
{
test: /\.html$/i,
use: ["html-loader"],
},
],
},
};Contributing
Please take a moment to read our contributing guidelines if you haven't yet done so.