code: function Pages(pages) {
    this.pages = [];
    if (typeof pages === 'undefined') return;
    if (!Array.isArray(pages)) {
      throw new TypeError('expected pages to be an Array');
    }
    this.addPages(pages);
  }
docs: Pages constructor
  
  ```js
  var pages = new Pages();
  ```
  
  @param {Array} `pages` Optional array of pages to initialize the `pages` array.
  @api public