Import CSS styles from NPM modules using rework.

This lets you use @import CSS using the same rules you use for require in Node. Specify the CSS file for a module using the style field in package.json and use @import "my-module";, or specify the file name in the module, like @import "my-module/my-file";. You can also require files relative to the current file using @import "./my-file";.

An @import will be processed so that the file referenced will have been imported in the current scope at the point of the @import. If a file has been previously imported in the current scope, that file will not be imported again. New scopes are created in a block such as a @media block. Child blocks will not duplicate imports that have been imported in the parent block, but may duplicate imports that are imported in a sibling block (since they may not have effect otherwise).

You can use source maps to show which file a definition originated from when debugging in a browser. To include inline source maps, use .toString({ sourcemap: true }) on the rework object when generating the output.

Note that to get correct import paths you must set the source option to the source file name when parsing the CSS source (usually with rework). If the source path is relative, it is resolved to the root option (defaults to the current directory). The source path is used to find the directory to start in when finding dependencies.

var rework = require('rework'),
    reworkNPM = require('rework-npm');

var output = rework('@import "test";', { source: 'my-file.css' })
    .use(reworkNPM())
    .toString();

console.log(output);

Creates a new plugin for rework that will import files from NPM.

The root directory for the source files. This is used for source maps to make imported file names relative to this directory, and for finding the absolute path for the top level source file.

Example:

// Uses `<dir>/src/index.css` as the file path for the top level file. Also all
// file paths in the source map will be relative to the `<dir>/src` folder.
rework('@import "./abc";', { source: 'index.css' })
    .use(reworkNPM({ root: path.join(__dirname, 'src') }))
    .toString();

If you need to import packages that do not specify a style property in their package.json or provide their styles in index.css, you can provide a shim config option to access them. This is specified as a hash whose keys are the names of packages to shim and whose values are the path, relative to that package's package.json file, where styles can be found.

Example:

// Imports the `dist/leaflet.css` file from the `leaflet` package
rework('@import "leaflet";', { source: 'index.css' })
    .use(reworkNPM({ shim: { 'leaflet': 'dist/leaflet.css' } }))
    .toString();

You can provide aliases for arbitrary import paths, including files and directories. When importing a file, it will search all directories in the path for aliases also. Note that relative imports are never aliased.

This is specified as an object where the keys are the name of the import path to alias, and the values are the file or directory path for the destination, relative to the root option.

Example:

// Imports the `styles/util.css` file
rework('@import "util";', { source: 'index.css' })
    .use(reworkNPM({ alias: { 'util': 'styles/util.css' } }))
    .toString();

// Imports the `styles/index.css` file if there is a `styles` directory,
// otherwise the `styles.css` file.
rework('@import "util";', { source: 'index.css' })
    .use(reworkNPM({ alias: { 'util': 'styles' } }))
    .toString();

// Imports the `styles/other.css` file
rework('@import "util/other";', { source: 'index.css' })
    .use(reworkNPM({ alias: { 'util': 'styles' } }))
    .toString();

A function that will be called before an imported file is parsed. This function will be called with the file contents and the full file path. This option can be used to convert other languages such as SCSS to CSS before importing.

Example:

// Process SCSS files
rework('@import "./some-file.scss";', { source: 'index.css' })
    .use(reworkNPM({ prefilter: compile }))
    .toString();

function compile(src, file) {
    if (path.extname(file) === '.scss') {
        return compileScss(src);
    }

    return src;
}