Function getSassImplementation

src/utils.js:114–166

* This function is not Webpack-specific and can be used by tools wishing to mimic `sass-loader`'s behaviour, so its signature should not be changed. * @param {SassImplementation | string | undefined} implementation sass implementation * @returns {Promise } resolved sass implemen

(implementation)

 * @returns {Promise<SassImplementation>} resolved sass implementation
 */
async function getSassImplementation(implementation) {
  /** @type {SassImplementation} */
  let resolvedImplementation;

  if (!implementation) {
    try {
      resolvedImplementation = /** @type {SassImplementation} */ (
        await import("sass-embedded")
      );
    } catch (err) {
      // Only fall back to `sass` when `sass-embedded` is not installed.
      // Any other failure (e.g. a broken install or a side-effect throw at
      // module-load time) should surface so the user can diagnose it
      // instead of being silently masked by the `sass` fallback.
      const { code } = /** @type {NodeJS.ErrnoException} */ (err);
      if (code !== "ERR_MODULE_NOT_FOUND" && code !== "MODULE_NOT_FOUND") {
        throw err;
      }

      resolvedImplementation = /** @type {SassImplementation} */ (
        await import("sass")
      );
    }
  } else if (typeof implementation === "string") {
    resolvedImplementation = /** @type {SassImplementation} */ (
      await import(normalizeImportSpecifier(implementation))
    );
  } else {
    resolvedImplementation = implementation;
  }

  const { info } = resolvedImplementation;

  if (!info) {
    throw new Error("Unknown Sass implementation.");
  }

  const infoParts = info.split("\t");

  if (infoParts.length < 2) {
    throw new Error(`Unknown Sass implementation "${info}".`);
  }

  const [implementationName] = infoParts;

  if (implementationName === "dart-sass") {
    return resolvedImplementation;
  } else if (implementationName === "sass-embedded") {
    return resolvedImplementation;
  }

  throw new Error(`Unknown Sass implementation "${implementationName}".`);
}

/**
 * @param {LoaderContext} loaderContext loader context