snowpack/dist-src/rollup-plugins/rollup-plugin-css.js

import { promises as fs } from 'fs';
function getInjectorCode(name, code) {
    return `
/** SNOWPACK INJECT STYLE: ${name} */
function __snowpack__injectStyle(css) {
  const headEl = document.head || document.getElementsByTagName('head')[0];
  const styleEl = document.createElement('style');
  styleEl.type = 'text/css';
  if (styleEl.styleSheet) {
    styleEl.styleSheet.cssText = css;
  } else {
    styleEl.appendChild(document.createTextNode(css));
  }
  headEl.appendChild(styleEl);
}
__snowpack__injectStyle(${JSON.stringify(code)});\n`;
}
/**
 * rollup-plugin-css
 *
 * Support installing any imported CSS into your dependencies. This isn't strictly valid
 * ESM code, but it is popular in the npm ecosystem & web development ecosystems. It also
 * solves a problem that is difficult to solve otherwise (referencing CSS from JS) so for
 * those reasons we have added default support for importing CSS into Snowpack v2.
 */
export function rollupPluginCss() {
    return {
        name: 'snowpack:rollup-plugin-css',
        resolveId(source, importer) {
            if (!source.endsWith('.css')) {
                return null;
            }
            return this.resolve(source, importer, { skipSelf: true }).then((resolved) => {
                return resolved || null;
            });
        },
        async load(id) {
            if (!id.endsWith('.css')) {
                return null;
            }
            const code = await fs.readFile(id, { encoding: 'utf8' });
            const humanReadableName = id.replace(/.*node_modules[\/\\]/, '').replace(/[\/\\]/g, '/');
            return getInjectorCode(humanReadableName, code);
        },
    };
}