stylus/lib/nodes/atrule.js

Robust, expressive, and feature-rich CSS superset

/*!
 * Stylus - at-rule
 * Copyright (c) Automattic <developer.wordpress.com>
 * MIT Licensed
 */

/**
 * Module dependencies.
 */

var Node = require('./node');

module.exports = class Atrule extends Node {
  /**
   * Initialize a new at-rule node.
   *
   * @param {String} type
   * @api public
   */

  constructor(type) {
    super()
    this.type = type;
  }

  /**
   * Check if at-rule's block has only properties.
   *
   * @return {Boolean}
   * @api public
   */

  get hasOnlyProperties() {
    if (!this.block) return false;

    var nodes = this.block.nodes;
    for (var i = 0, len = nodes.length; i < len; ++i) {
      var nodeName = nodes[i].nodeName;
      switch (nodes[i].nodeName) {
        case 'property':
        case 'expression':
        case 'comment':
          continue;
        default:
          return false;
      }
    }
    return true;
  }

  /**
   * Return a clone of this node.
   *
   * @return {Node}
   * @api public
   */

  clone(parent) {
    var clone = new Atrule(this.type);
    if (this.block) clone.block = this.block.clone(parent, clone);
    clone.segments = this.segments.map(function (node) { return node.clone(parent, clone); });
    clone.lineno = this.lineno;
    clone.column = this.column;
    clone.filename = this.filename;
    return clone;
  };

  /**
   * Return a JSON representation of this node.
   *
   * @return {Object}
   * @api public
   */

  toJSON() {
    var json = {
      __type: 'Atrule',
      type: this.type,
      segments: this.segments,
      lineno: this.lineno,
      column: this.column,
      filename: this.filename
    };
    if (this.block) json.block = this.block;
    return json;
  };

  /**
   * Return @<type>.
   *
   * @return {String}
   * @api public
   */

  toString() {
    return '@' + this.type;
  };

  /**
   * Check if the at-rule's block has output nodes.
   *
   * @return {Boolean}
   * @api public
   */

  get hasOutput() {
    return !!this.block && hasOutput(this.block);
  };
};

function hasOutput(block) {
  var nodes = block.nodes;

  // only placeholder selectors
  if (nodes.every(function (node) {
    return 'group' == node.nodeName && node.hasOnlyPlaceholders;
  })) return false;

  // something visible
  return nodes.some(function (node) {
    switch (node.nodeName) {
      case 'property':
      case 'literal':
      case 'import':
        return true;
      case 'block':
        return hasOutput(node);
      default:
        if (node.block) return hasOutput(node.block);
    }
  });
}