Exports HTML as string. HTML is minimized when the compiler demands.
To begin, you'll need to install html-loader
:
npm install --save-dev html-loader
or
yarn add -D html-loader
or
pnpm add -D html-loader
Then 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",
},
],
},
};
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 import img from "./image.png""
).
You may need to specify loaders for images in your configuration (recommended asset modules
).
Supported tags and attributes:
- the
src
attribute of theaudio
tag - the
src
attribute of theembed
tag - the
src
attribute of theimg
tag - the
srcset
attribute of theimg
tag - the
src
attribute of theinput
tag - the
data
attribute of theobject
tag - the
src
attribute of thescript
tag - the
href
attribute of thescript
tag - the
xlink:href
attribute of thescript
tag - the
src
attribute of thesource
tag - the
srcset
attribute of thesource
tag - the
src
attribute of thetrack
tag - the
poster
attribute of thevideo
tag - the
src
attribute of thevideo
tag - the
xlink:href
attribute of theimage
tag - the
href
attribute of theimage
tag - the
xlink:href
attribute of theuse
tag - the
href
attribute of theuse
tag - the
href
attribute of thelink
tag when therel
attribute containsstylesheet
,icon
,shortcut icon
,mask-icon
,apple-touch-icon
,apple-touch-icon-precomposed
,apple-touch-startup-image
,manifest
,prefetch
,preload
or when theitemprop
attribute isimage
,logo
,screenshot
,thumbnailurl
,contenturl
,downloadurl
,duringmedia
,embedurl
,installurl
,layoutimage
- the
imagesrcset
attribute of thelink
tag when therel
attribute containsstylesheet
,icon
,shortcut icon
,mask-icon
,apple-touch-icon
,apple-touch-icon-precomposed
,apple-touch-startup-image
,manifest
,prefetch
,preload
- the
content
attribute of themeta
tag when thename
attribute ismsapplication-tileimage
,msapplication-square70x70logo
,msapplication-square150x150logo
,msapplication-wide310x150logo
,msapplication-square310x310logo
,msapplication-config
,twitter:image
or when theproperty
attribute isog:image
,og:image:url
,og:image:secure_url
,og:audio
,og:audio:secure_url
,og:video
,og:video:secure_url
,vk:image
or when theitemprop
attribute isimage
,logo
,screenshot
,thumbnailurl
,contenturl
,downloadurl
,duringmedia
,embedurl
,installurl
,layoutimage
- the
icon-uri
value component incontent
attribute of themeta
tag when thename
attribute ismsapplication-task
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,
},
},
],
},
};
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;
},
},
},
},
],
},
};
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
tag
option takes precedence over source without.
Filter can be used to disable default sources.
For example:
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
sources: {
list: [
"...",
{
tag: "img",
attribute: "src",
type: "src",
filter: () => false,
},
],
},
},
},
],
},
};
Type:
type urlFilter = (
attribute: string,
value: string,
resourcePath: string,
) => boolean;
Default: undefined
Allow to filter urls. All filtered urls will not be resolved (left in the code as they were written).
Non-requestable sources (for example <img src="javascript:void(0)">
) are not handled by default.
module.exports = {
module: {
rules: [
{
test: /\.html$/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$/.test(value)) {
return false;
}
return true;
},
},
},
},
],
},
};
Type:
type scriptingEnabled = boolean;
Default: true
By default, the parser in html-loader
interprets content inside <noscript>
tags as #text
, so processing of content inside this tag will be ignored.
In order to enable processing inside <noscript>
for content recognition by the parser as #AST
, set this parameter to: false
Additional information: scriptingEnabled
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
sources: {
// Enables processing inside the <noscript> tag
scriptingEnabled: false,
},
},
},
],
},
};
Type:
type preprocessor = (
content: string | Buffer,
loaderContext: LoaderContext,
) => HTMLElement;
Default: undefined
Allows pre-processing of content before handling.
Warning
You should always return valid HTML
file.hbs
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;
},
},
},
],
},
};
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.
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$/i,
loader: "html-loader",
options: {
minimize: true,
},
},
],
},
};
webpack.config.js
See html-minifier-terser's documentation for more information on the available options.
The default rules can be overridden using the following options in your webpack.conf.js
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.html$/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$/i,
loader: "html-loader",
options: {
minimize: {
...defaultMinimizerOptions,
removeComments: false,
collapseWhitespace: false,
},
},
},
],
},
};
Type:
type esModule = boolean;
Default: true
By default, html-loader
generates JS modules that use the ES modules syntax.
There are some cases in which using ES modules is beneficial, such as module concatenation and tree shaking.
You can enable a CommonJS modules syntax using:
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.html$/i,
loader: "html-loader",
options: {
esModule: false,
},
},
],
},
};
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" />
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 resolved
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,..." >'
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",
},
],
},
};
You can use any template system. Below is an example for handlebars.
file.hbs
webpack.config.js
const Handlebars = require("handlebars");
module.exports = {
module: {
rules: [
{
test: /\.hbs$/i,
loader: "html-loader",
options: {
preprocessor: (content, loaderContext) => {
let result;
try {
result = Handlebars.compile(content)({
firstname: "Value",
lastname: "OtherValue",
});
} catch (error) {
loaderContext.emitError(error);
return content;
}
return result;
},
},
},
],
},
};
You can use PostHTML without any additional loaders.
file.html
<img src="image.jpg" />
webpack.config.js
const posthtml = require("posthtml");
const posthtmlWebp = require("posthtml-webp");
module.exports = {
module: {
rules: [
{
test: /\.hbs$/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;
},
},
},
],
},
};
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"],
},
],
},
};
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