I'm rendering JSON dates that look like this: /Date(1185336000000)/ and I'm trying to convert them to a ("mmmm d, yyyy")-type format.
I tried a if...includes() and then a format() method, but they didn't work (bad syntax) and they disabled already rendered data.  
JS snippet:
import firmData from '../JSON/firmDir.json';
function loadBio() {
let dateOfHire = firmData.d.results.map(function(val) {
      // if (val.hiredate === null || undefined) return " ";
      let newDate = val.hiredate;
      if (newDate.includes('000')) {
           newDate.format("mmmm d, yyyy");
      }
    return val.hiredate
 })
$("#hireDate-id").append(dateOfHire);
}
loadBio()
JSON snippet:
{
  "d": {
    "results": [
      {
       "hiredate": "/Date(1185336000000)/",
       ...
 
    