parcel-bundler/lib/assets/StylusAsset.js

<p align="center"> <a href="https://parceljs.org/" target="_blank"> <img alt="Parcel" src="https://user-images.githubusercontent.com/19409/31321658-f6aed0f2-ac3d-11e7-8100-1587e676e0ec.png" width="749"> </a> </p>

'use strict';

let createEvaluator = (() => {
  var _ref = _asyncToGenerator(function* (asset) {
    const Evaluator = yield localRequire('stylus/lib/visitor/evaluator', asset.name);
    const utils = yield localRequire('stylus/lib/utils', asset.name);
    const resolver = new Resolver(asset.options);

    // This is a custom stylus evaluator that extends stylus with support for the node
    // require resolution algorithm. It also adds all dependencies to the parcel asset
    // tree so the file watcher works correctly, etc.
    class CustomEvaluator extends Evaluator {
      visitImport(imported) {
        let node = this.visit(imported.path).first;
        let path = node.string;
        if (node.name !== 'url' && path && !URL_RE.test(path)) {
          try {
            // First try resolving using the node require resolution algorithm.
            // This allows stylus files in node_modules to be resolved properly.
            // If we find something, update the AST so stylus gets the absolute path to load later.
            node.string = resolver.resolveSync(path, imported.filename).path;
            asset.addDependency(node.string, { includedInParent: true });
          } catch (err) {
            // If we couldn't resolve, try the normal stylus resolver.
            // We just need to do this to keep track of the dependencies - stylus does the real work.

            // support optional .styl
            if (!/\.styl$/i.test(path)) {
              path += '.styl';
            }

            let found = utils.find(path, this.paths, this.filename);
            if (!found) {
              found = utils.lookupIndex(node.string, this.paths, this.filename);
            }

            if (!found) {
              let nodeName = imported.once ? 'require' : 'import';
              throw new Error('failed to locate @' + nodeName + ' file ' + node.string);
            }

            var _iteratorNormalCompletion = true;
            var _didIteratorError = false;
            var _iteratorError = undefined;

            try {
              for (var _iterator = found[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
                let file = _step.value;

                asset.addDependency(file, { includedInParent: true });
              }
            } catch (err) {
              _didIteratorError = true;
              _iteratorError = err;
            } finally {
              try {
                if (!_iteratorNormalCompletion && _iterator.return) {
                  _iterator.return();
                }
              } finally {
                if (_didIteratorError) {
                  throw _iteratorError;
                }
              }
            }
          }
        }

        // Done. Let stylus do its thing.
        return super.visitImport(imported);
      }
    }

    return CustomEvaluator;
  });

  return function createEvaluator(_x) {
    return _ref.apply(this, arguments);
  };
})();

function _asyncToGenerator(fn) { return function () { var gen = fn.apply(this, arguments); return new Promise(function (resolve, reject) { function step(key, arg) { try { var info = gen[key](arg); var value = info.value; } catch (error) { reject(error); return; } if (info.done) { resolve(value); } else { return Promise.resolve(value).then(function (value) { step("next", value); }, function (err) { step("throw", err); }); } } return step("next"); }); }; }

const CSSAsset = require('./CSSAsset');
const config = require('../utils/config');
const localRequire = require('../utils/localRequire');
const Resolver = require('../Resolver');

const URL_RE = /^(?:url\s*\(\s*)?['"]?(?:[#/]|(?:https?:)?\/\/)/i;

class StylusAsset extends CSSAsset {
  parse(code) {
    var _this = this;

    return _asyncToGenerator(function* () {
      // stylus should be installed locally in the module that's being required
      let stylus = yield localRequire('stylus', _this.name);
      let opts = _this.package.stylus || (yield config.load(_this.name, ['.stylusrc', '.stylusrc.js']));
      let style = stylus(code, opts);
      style.set('filename', _this.name);
      style.set('include css', true);
      style.set('Evaluator', (yield createEvaluator(_this)));

      // Setup a handler for the URL function so we add dependencies for linked assets.
      style.define('url', function (node) {
        let filename = _this.addURLDependency(node.val, node.filename);
        return new stylus.nodes.Literal(`url(${JSON.stringify(filename)})`);
      });

      return style;
    })();
  }

  collectDependencies() {
    // Do nothing. Dependencies are collected by our custom evaluator.
  }

  generateErrorMessage(err) {
    let index = err.message.indexOf('\n');
    err.codeFrame = err.message.slice(index + 1);
    err.message = err.message.slice(0, index);
    return err;
  }
}

module.exports = StylusAsset;