loader-utils

What is loader-utils?

The loader-utils package provides utility functions for use with webpack loaders. It offers a variety of helper methods to make writing loaders easier and more standardized. These utilities include parsing query strings, hashing, getting options from loaders, and more.

What are loader-utils's main functionalities?

getOptions

This function is used to parse the options passed to a loader. It simplifies the process of handling loader options within a webpack configuration.

const loaderUtils = require('loader-utils');
const options = loaderUtils.getOptions(this);

stringifyRequest

This method helps to convert a module request into a string that can be used inside of a loader. It's useful for ensuring that the request is correctly formatted and can be resolved by webpack.

const loaderUtils = require('loader-utils');
const stringifiedRequest = loaderUtils.stringifyRequest(this, require.resolve('./file.js'));

getHashDigest

This utility generates a hash digest of the given content. It's commonly used for cache busting or to generate unique identifiers for file contents.

const loaderUtils = require('loader-utils');
const hashDigest = loaderUtils.getHashDigest(Buffer.from('some content'), 'sha512', 'hex', 7);

interpolateName

This function allows for the creation of a custom filename based on placeholders and content. It's often used in file-loader and url-loader to generate names based on the file content.

const loaderUtils = require('loader-utils');
const interpolatedName = loaderUtils.interpolateName(this, '[name]_[hash].[ext]', { content: source });

Other packages similar to loader-utils

schema-utils

Schema-utils validates options for webpack loaders and plugins against a JSON Schema. It is similar to loader-utils in that it helps with managing loader options, but it focuses on validation rather than utility functions.

file-loader

File-loader resolves import/require() on a file into a url and emits the file into the output directory. It's similar to loader-utils' interpolateName feature but is a standalone loader that focuses on file handling.

url-loader

Url-loader works like file-loader but can return a Data URL if the file is smaller than a byte limit. It shares some functionality with loader-utils, particularly in generating filenames and paths.