notes/node_modules/doiuse/lib/detect-feature-use.js

'use strict';

var _createClass = (function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ('value' in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; })();

function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) arr2[i] = arr[i]; return arr2; } else { return Array.from(arr); } }

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError('Cannot call a class as a function'); } }

var _ = require('lodash');
var features = require('../data/features');

var PLUGIN_OPTION_COMMENT = 'doiuse-';
var DISABLE_FEATURE_COMMENT = PLUGIN_OPTION_COMMENT + 'disable';
var ENABLE_FEATURE_COMMENT = PLUGIN_OPTION_COMMENT + 'enable';

/*
 * str: string to search in.
 * searchfor: string or pattern to search for.
 */
function isFoundIn(str) {
  str = stripUrls(str);
  return function find(searchfor) {
    if (searchfor instanceof RegExp) return searchfor.test(str);else if (_.isFunction(searchfor)) return searchfor(str);else return str && str.indexOf(searchfor) >= 0;
  };
}

/*
 * Strip the contents of url literals so they aren't matched
 * by our naive substring matching.
 */
function stripUrls(str) {
  return str.replace(/url\([^\)]*\)/g, 'url()');
}

/**
 * Detect the use of any of a given list of CSS features.
 * ```
 * var detector = new Detector(featureList)
 * detector.process(css, cb)
 * ```
 *
 * `featureList`: an array of feature slugs (see caniuse-db)
 * `cb`: a callback that gets called for each usage of one of the given features,
 * called with an argument like:
 * ```
 * {
 *   usage: {} // postcss node where usage was found
 *   feature: {} // caniuse-db feature slug
 *   ignore: {} // caniuse-db feature to ignore in current file
 * }
 * ```
 */
module.exports = (function () {
  function Detector(featureList) {
    _classCallCheck(this, Detector);

    this.features = _.pick(features, featureList);
    this.ignore = [];
  }

  _createClass(Detector, [{
    key: 'decl',
    value: function decl(_decl, cb) {
      for (var feat in this.features) {
        var properties = this.features[feat].properties || [];
        var values = this.features[feat].values;
        if (properties.filter(isFoundIn(_decl.prop)).length > 0) {
          if (!values || values.filter(isFoundIn(_decl.value)).length > 0) {
            cb({ usage: _decl, feature: feat, ignore: this.ignore });
          }
        }
      }
    }
  }, {
    key: 'rule',
    value: function rule(_rule, cb) {
      for (var feat in this.features) {
        var selectors = this.features[feat].selectors || [];
        if (selectors.filter(isFoundIn(_rule.selector)).length > 0) {
          cb({ usage: _rule, feature: feat, ignore: this.ignore });
        }
      }

      this.node(_rule, cb);
    }
  }, {
    key: 'atrule',
    value: function atrule(_atrule, cb) {
      for (var feat in this.features) {
        var atrules = this.features[feat].atrules || [];
        var params = this.features[feat].params;
        if (atrules.filter(isFoundIn(_atrule.name)).length > 0) {
          if (!params || params.filter(isFoundIn(_atrule.params)).length > 0) {
            cb({ usage: _atrule, feature: feat, ignore: this.ignore });
          }
        }
      }

      this.node(_atrule, cb);
    }
  }, {
    key: 'comment',
    value: function comment(_comment, cb) {
      var text = _comment.text.toLowerCase();

      if (_.startsWith(text, PLUGIN_OPTION_COMMENT)) {
        var option = text.split(' ', 1)[0];
        var value = text.replace(option, '').trim();

        switch (option) {
          case DISABLE_FEATURE_COMMENT:
            if (value === '') {
              this.ignore = _.keysIn(this.features);
            } else {
              this.ignore = _.uniq([].concat(_toConsumableArray(this.ignore), _toConsumableArray(value.split(',').map(function (feat) {
                return feat.trim();
              }))));
            }
            break;
          case ENABLE_FEATURE_COMMENT:
            if (value === '') {
              this.ignore = [];
            } else {
              this.ignore = _.without.apply(_, [this.ignore].concat(_toConsumableArray(value.split(',').map(function (feat) {
                return feat.trim();
              }))));
            }
            break;
        }
      }
    }
  }, {
    key: 'node',
    value: function node(_node, cb) {
      var _this = this;

      _node.each(function (child) {
        switch (child.type) {
          case 'rule':
            _this.rule(child, cb);
            break;
          case 'decl':
            _this.decl(child, cb);
            break;
          case 'atrule':
            _this.atrule(child, cb);
            break;
          case 'comment':
            _this.comment(child, cb);
            break;
          default:
            throw new Error('Unkonwn node type ' + child.type);
        }
      });
    }
  }, {
    key: 'process',
    value: function process(node, cb) {
      //  Reset ignoring rules specified by inline comments per each file
      this.ignore = [];

      //  Recursively walk nodes in file
      this.node(node, cb);
    }
  }]);

  return Detector;
})();