title: jqGrid custom formatter
body: <p>For one of the columns in my jqGrid, I'm providing a custom formatter function.  I'm providing some special cases, but if those conditions aren't met, I'd like to resort to using the built-in date formatter utility method.  It doesn't seem that I'm getting the right combination of $.extend() to create the options that method is expecting.</p>
  
  <p>My colModel for this column:</p>
  
  <pre><code>{ name:'expires', 
      index:'7',
      width:90,
      align:"right",
      resizable: false,
      formatter: expireFormat,
      formatoptions: {srcformat:"l, F d, Y g:i:s A",newformat:"n/j/Y"}
  },
  </code></pre>
  
  <p>And an example of what I'm trying to do</p>
  
  <pre><code>function expireFormat(cellValue, opts, rowObject) {
      if (cellValue == null || cellValue == 1451520000) {
          // a specific date that should show as blank
          return '';
      } else {
          // here is where I'd like to just call the $.fmatter.util.DateFormat
          var dt = new Date(cellValue * 1000);
          var op = $.extend({},opts.date);
          if(!isUndefined(opts.colModel.formatoptions)) {
              op = $.extend({},op,opts.colModel.formatoptions);
          }
          return $.fmatter.util.DateFormat(op.srcformat,dt,op.newformat,op);
      }
  }
  </code></pre>
  
  <p>(An exception is being thrown in the guts of that DateFormat method, looks like where it's trying to read into a masks property of the options that get passed in)</p>
  
  <p><strong>EDIT:</strong></p>
  
  <p>The $.extend that put everything in the place it needed was getting it from that global property where the i18n library set it, <strong>$.jgrid.formatter.date</strong>.</p>
  
  <pre><code>var op = $.extend({}, $.jgrid.formatter.date);
  if(!isUndefined(opts.colModel.formatoptions)) {
      op = $.extend({}, op, opts.colModel.formatoptions);
  }
  return $.fmatter.util.DateFormat(op.srcformat,dt.toLocaleString(),op.newformat,op);
  </code></pre>