function Declaration(defaults) {
    _classCallCheck(this, Declaration);

    var _this = _possibleConstructorReturn(this, _Node.call(this, defaults));

    _this.type = 'decl';
    return _this;
  }
Represents a CSS declaration.

@extends Node

@example
const root = postcss.parse('a { color: black }');
const decl = root.first.first;
decl.type       //=> 'decl'
decl.toString() //=> ' color: black'