rule.js

let Container = require('./container')
let list = require('./list')

/**
 * Represents a CSS rule: a selector followed by a declaration block.
 *
 * @extends Container
 *
 * @example
 * const root = postcss.parse('a{}')
 * const rule = root.first
 * rule.type       //=> 'rule'
 * rule.toString() //=> 'a{}'
 */
class Rule extends Container {
  constructor (defaults) {
    super(defaults)
    this.type = 'rule'
    if (!this.nodes) this.nodes = []
  }

  /**
   * An array containing the rule’s individual selectors.
   * Groups of selectors are split at commas.
   *
   * @type {string[]}
   *
   * @example
   * const root = postcss.parse('a, b { }')
   * const rule = root.first
   *
   * rule.selector  //=> 'a, b'
   * rule.selectors //=> ['a', 'b']
   *
   * rule.selectors = ['a', 'strong']
   * rule.selector //=> 'a, strong'
   */
  get selectors () {
    return list.comma(this.selector)
  }

  set selectors (values) {
    let match = this.selector ? this.selector.match(/,\s*/) : null
    let sep = match ? match[0] : ',' + this.raw('between', 'beforeOpen')
    this.selector = values.join(sep)
  }

  /**
   * @memberof Rule#
   * @member {string} selector The rule’s full selector represented
   *                           as a string.
   *
   * @example
   * const root = postcss.parse('a, b { }')
   * const rule = root.first
   * rule.selector //=> 'a, b'
   */

  /**
   * @memberof Rule#
   * @member {object} raws Information to generate byte-to-byte equal
   *                       node string as it was in the origin input.
   *
   * Every parser saves its own properties,
   * but the default CSS parser uses:
   *
   * * `before`: the space symbols before the node. It also stores `*`
   *   and `_` symbols before the declaration (IE hack).
   * * `after`: the space symbols after the last child of the node
   *   to the end of the node.
   * * `between`: the symbols between the property and value
   *   for declarations, selector and `{` for rules, or last parameter
   *   and `{` for at-rules.
   * * `semicolon`: contains `true` if the last child has
   *   an (optional) semicolon.
   * * `ownSemicolon`: contains `true` if there is semicolon after rule.
   *
   * PostCSS cleans selectors from comments and extra spaces,
   * but it stores origin content in raws properties.
   * As such, if you don’t change a declaration’s value,
   * PostCSS will use the raw value with comments.
   *
   * @example
   * const root = postcss.parse('a {\n  color:black\n}')
   * root.first.first.raws //=> { before: '', between: ' ', after: '\n' }
   */
}

module.exports = Rule

Container.registerRule(Rule)