code: function parseOptions (options) {
    return {
      [ELEMENT_TYPE.NORMAL]: (options && options.html && options.html.normal) || 'always',
      [ELEMENT_TYPE.VOID]: (options && options.html && options.html.void) || 'never',
      [ELEMENT_TYPE.COMPONENT]: (options && options.html && options.html.component) || 'always',
      [ELEMENT_TYPE.SVG]: (options && options.svg) || 'always',
      [ELEMENT_TYPE.MATH]: (options && options.math) || 'always'
    }
  }
docs: Normalize the given options.
  @param {Object|undefined} options The raw options object.
  @returns {Object} Normalized options.