postcss-lightningcss/src/options.js

PostCSS plugin to use lightningcss

const browserslist = require('browserslist');
const css = require('lightningcss');

const defaultLightningcssOptions = {
  minify: true
};

function prepareGlobalOptions (dir, pluginOptions = {}) {
  const lightningcssOptions = {
    ...defaultLightningcssOptions,
    ...(pluginOptions.lightningcssOptions || {})
  };

  let browserslistConfig;
  if (pluginOptions.browsers != null) {
    browserslistConfig = pluginOptions.browsers;
  } else {
    // try to find a browserslist config
    browserslistConfig = browserslist.loadConfig({ path: dir });
  }

  // lightningcss uses a custom syntax to declare supported browsers
  // the `browsers` option provides a helper to declare them with
  // a `browerslist` query
  if (browserslistConfig) {
    const browsers = browserslist(browserslistConfig);
    lightningcssOptions.targets = css.browserslistToTargets(browsers);
  }

  return lightningcssOptions;
}

function setCssModulesOption (filename, options, pluginOptions) {
  let cssModules = pluginOptions.cssModules;

  if (!cssModules) {
    return;
  }

  if (cssModules === 'auto') {
    cssModules = /\.module(s)?\.\w+$/i;
  }

  if (cssModules instanceof RegExp) {
    options.cssModules = cssModules.test(filename);
    return;
  }

  // At this stage, cssModules is a truthy value
  // and pass it through
  options.cssModules = cssModules;
}

function prepareOptions (filename, map, lightningcssOptions, pluginOptions) {
  const options = {
    filename,
    sourceMap: !!map,
    ...lightningcssOptions
  };

  if (!Object.prototype.hasOwnProperty.call(options, 'cssModules')) {
    setCssModulesOption(filename, options, pluginOptions);
  }

  return options;
}

module.exports = { prepareGlobalOptions, prepareOptions };