url-loader
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Package description
The url-loader npm package is used within web development environments to encode files as Base64 URLs and include them inline in the code. It is often used with webpack to handle images, fonts, and other file types within JavaScript and CSS files. When the file size is below a specified limit, url-loader will transform the file into a Data URL; otherwise, it falls back to file-loader, which handles larger files by emitting them to a separate file and returns the file URL.
Encode files as Data URLs
This webpack configuration uses url-loader to process image files. If an image is smaller than 8KB, it will be converted to a Base64 encoded Data URL and inlined in the code. Larger images will be handled by file-loader, which is the default fallback.
module.exports = {
module: {
rules: [
{
test: /\.(png|jpg|gif)$/i,
use: [
{
loader: 'url-loader',
options: {
limit: 8192
}
}
]
}
]
}
};Fallback to file-loader
In this example, url-loader is configured with a fallback option. If the file size exceeds the limit, file-loader is used to emit the file to the output directory and returns the public URL. The 'name' option specifies the naming convention for the emitted files.
module.exports = {
module: {
rules: [
{
test: /\.(png|jpg|gif)$/i,
use: [
{
loader: 'url-loader',
options: {
limit: 8192,
fallback: 'file-loader',
name: '[path][name].[ext]'
}
}
]
}
]
}
};file-loader resolves import/require() on a file into a url and emits the file into the output directory. It is similar to url-loader but does not convert files to Data URLs. It is often used as a fallback for url-loader when files exceed the specified limit.
raw-loader loads files as a string and is similar to url-loader in the sense that it allows the inclusion of file contents inline in the code. However, it does not encode the files to Base64, nor does it have a fallback mechanism like url-loader.
svg-url-loader is designed specifically for SVG files. It encodes SVGs into compact Data URLs, similar to what url-loader does for general files. It has optimizations for SVGs, such as removing unnecessary whitespace, newlines, and comments, which url-loader does not perform by default.
Changelog
3.0.0 (2019-11-26)
10.13.0esModules option to esModuleesModule is true by default)Readme
A loader for webpack which transforms files into base64 URIs.
To begin, you'll need to install url-loader:
$ npm install url-loader --save-dev
url-loader works like
file-loader, but can return
a DataURL if the file is smaller than a byte limit.
index.js
import img from './image.png';
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.(png|jpg|gif)$/i,
use: [
{
loader: 'url-loader',
options: {
limit: 8192,
},
},
],
},
],
},
};
And run webpack via your preferred method.
fallbackType: String
Default: 'file-loader'
Specifies an alternative loader to use when a target file's size exceeds the
limit set in the limit option.
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.(png|jpg|gif)$/i,
use: [
{
loader: 'url-loader',
options: {
fallback: require.resolve('responsive-loader'),
},
},
],
},
],
},
};
The fallback loader will receive the same configuration options as url-loader.
For example, to set the quality option of a responsive-loader above use:
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.(png|jpg|gif)$/i,
use: [
{
loader: 'url-loader',
options: {
fallback: require.resolve('responsive-loader'),
quality: 85,
},
},
],
},
],
},
};
limitType: Number|Boolean|String
Default: undefined
The limit can be specified via loader options and defaults to no limit.
Number|StringA Number or String specifying the maximum size of a file in bytes. If the file size is
equal or greater than the limit file-loader
will be used (by default) and all query parameters are passed to it.
Using an alternative to file-loader is enabled via the fallback option.
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.(png|jpg|gif)$/i,
use: [
{
loader: 'url-loader',
options: {
limit: 8192,
},
},
],
},
],
},
};
BooleanEnable or disable transform files into base64.
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.(png|jpg|gif)$/i,
use: [
{
loader: 'url-loader',
options: {
limit: false,
},
},
],
},
],
},
};
mimetypeType: String
Default: (file extension)
Sets the MIME type for the file to be transformed. If unspecified the file extensions will be used to lookup the MIME type.
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.(png|jpg|gif)$/i,
use: [
{
loader: 'url-loader',
options: {
mimetype: 'image/png',
},
},
],
},
],
},
};
esModuleType: Boolean
Default: true
By default, file-loader generates JS modules that use the ES modules syntax.
There are some cases in which using ES modules is beneficial, like in the case of module concatenation and tree shaking.
You can enable a CommonJS module syntax using:
webpack.config.js
module.exports = {
module: {
rules: [
{
test: /\.css$/,
use: [
{
loader: 'url-loader',
options: {
esModule: false,
},
},
],
},
],
},
};
Please take a moment to read our contributing guidelines if you haven't yet done so.
FAQs
A loader for webpack which transforms files into base64 URIs
The npm package url-loader receives a total of 4,144,159 weekly downloads. As such, url-loader popularity was classified as popular.
We found that url-loader demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 6 open source maintainers collaborating on the project.
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