less-loader/dist/utils.js

A Less loader for webpack. Compiles Less to CSS.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.getLessImplementation = getLessImplementation;
exports.getLessOptions = getLessOptions;

var _less = _interopRequireDefault(require("less"));

var _clone = _interopRequireDefault(require("clone"));

var _loaderUtils = require("loader-utils");

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

/* eslint-disable class-methods-use-this */
const trailingSlash = /[/\\]$/; // This somewhat changed in Less 3.x. Now the file name comes without the
// automatically added extension whereas the extension is passed in as `options.ext`.
// So, if the file name matches this regexp, we simply ignore the proposed extension.

const isModuleName = /^~([^/]+|[^/]+\/|@[^/]+[/][^/]+|@[^/]+\/?|@[^/]+[/][^/]+\/)$/;
/**
 * Creates a Less plugin that uses webpack's resolving engine that is provided by the loaderContext.
 *
 * @param {LoaderContext} loaderContext
 * @returns {LessPlugin}
 */

function createWebpackLessPlugin(loaderContext) {
  const resolve = loaderContext.getResolve({
    mainFields: ['less', 'style', 'main', '...'],
    mainFiles: ['index', '...'],
    extensions: ['.less', '.css']
  });

  class WebpackFileManager extends _less.default.FileManager {
    supports(filename) {
      if (this.isPathAbsolute(filename)) {
        return false;
      }

      return true;
    } // Sync resolving is used at least by the `data-uri` function.
    // This file manager doesn't know how to do it, so let's delegate it
    // to the default file manager of Less.
    // We could probably use loaderContext.resolveSync, but it's deprecated,
    // see https://webpack.js.org/api/loaders/#this-resolvesync


    supportsSync() {
      return false;
    }

    getUrl(filename, options) {
      if (options.ext && !isModuleName.test(filename)) {
        return this.tryAppendExtension(filename, options.ext);
      }

      return filename;
    }

    async resolveFilename(filename, currentDirectory, options) {
      const url = this.getUrl(filename, options);
      const moduleRequest = (0, _loaderUtils.urlToRequest)(url, url.charAt(0) === '/' ? '' : null); // Less is giving us trailing slashes, but the context should have no trailing slash

      const context = currentDirectory.replace(trailingSlash, '');
      return this.resolveRequests(context, [moduleRequest, url]);
    }

    resolveRequests(context, possibleRequests) {
      if (possibleRequests.length === 0) {
        return Promise.reject();
      }

      return resolve(context, possibleRequests[0]).then(result => {
        return result;
      }).catch(error => {
        const [, ...tailPossibleRequests] = possibleRequests;

        if (tailPossibleRequests.length === 0) {
          throw error;
        }

        return this.resolveRequests(context, tailPossibleRequests);
      });
    }

    async loadFile(filename, ...args) {
      let result;

      try {
        if (isModuleName.test(filename)) {
          const error = new Error();
          error.type = 'Next';
          throw error;
        }

        result = await super.loadFile(filename, ...args);
      } catch (error) {
        if (error.type !== 'File' && error.type !== 'Next') {
          return Promise.reject(error);
        }

        try {
          result = await this.resolveFilename(filename, ...args);
        } catch (webpackResolveError) {
          error.message = `Less resolver error:\n${error.message}\n\n` + `Webpack resolver error details:\n${webpackResolveError.details}\n\n` + `Webpack resolver error missing:\n${webpackResolveError.missing}\n\n`;
          return Promise.reject(error);
        }

        loaderContext.addDependency(result);
        return super.loadFile(result, ...args);
      }

      loaderContext.addDependency(result.filename);
      return result;
    }

  }

  return {
    install(lessInstance, pluginManager) {
      pluginManager.addFileManager(new WebpackFileManager());
    },

    minVersion: [3, 0, 0]
  };
}
/**
 * Get the less options from the loader context and normalizes its values
 *
 * @param {object} loaderContext
 * @param {object} loaderOptions
 * @returns {Object}
 */


function getLessOptions(loaderContext, loaderOptions) {
  const options = (0, _clone.default)(loaderOptions.lessOptions ? typeof loaderOptions.lessOptions === 'function' ? loaderOptions.lessOptions(loaderContext) || {} : loaderOptions.lessOptions : {});
  const lessOptions = {
    plugins: [],
    relativeUrls: true,
    // We need to set the filename because otherwise our WebpackFileManager will receive an undefined path for the entry
    filename: loaderContext.resourcePath,
    ...options
  };
  lessOptions.plugins.unshift(createWebpackLessPlugin(loaderContext));
  const useSourceMap = typeof loaderOptions.sourceMap === 'boolean' ? loaderOptions.sourceMap : loaderContext.sourceMap;

  if (useSourceMap) {
    lessOptions.sourceMap = {
      outputSourceFiles: true
    };
  }

  return lessOptions;
}

function getLessImplementation(implementation) {
  if (typeof implementation !== 'undefined') {
    return implementation;
  }

  return _less.default;
}