message: added options object warning to `createShadowElement`
diff: @@ -1872,13 +1872,17 @@ function getExcelColName(length: number):string {
  * @param {Object} opts optional shadow properties
  * @param {Object} defaults defaults for unspecified properties in `opts`
  * @see http://officeopenxml.com/drwSp-effects.php
  - * { type: 'outer', blur: 3, offset: (23000 / 12700), angle: 90, color: '000000', opacity: 0.35, rotateWithShape: true };
  + * @example { type: 'outer', blur: 3, offset: (23000 / 12700), angle: 90, color: '000000', opacity: 0.35, rotateWithShape: true };
  * @return {string} XML
  */
  function createShadowElement(options: IShadowOptions, defaults: object): string {
  - if (options === null) {
  + if (!options) {
  + return '<a:effectLst/>'
  + } else if (typeof options !== 'object') {
  + console.warn("`shadow` options must be an object. Ex: `{shadow: {type:'none'}}`")
  return '<a:effectLst/>'
  }
  +
  let strXml = '<a:effectLst>',
  opts = getMix(defaults, options),
  type = opts['type'] || 'outer',
  