title: indexof is not a function in typescript while filter based on number
body: <p>When i try to filter month value on dropdown it shows indexof() is  not function ..
  The code is ..</p>
  
  <pre><code>@Pipe({
      name: "monthFilter",
  })
  export class MonthStatusPipe implements PipeTransform {
        transform(array: any[], query: number): any {  
          console.log("query", query);
          if (query) {
              return _.filter(array, row =&gt; row.LicenseMonth.indexOf(query) &gt; -1);
          }
          return array;
      }
  }
  </code></pre>
  
  <p>Is there any alternative method to filter dropdown based on values..</p>
  
  <p>My json data are:</p>
  
  <pre><code>{
      "BusinessId": 1549,
      "OrganizationNumber": "992060867",
      "CompanyName": "Litra Containerservice AS ",
      "Address": "Industrigata 62",
      "Zipcode": "2619 Lillehammer",
      "Mobile": "98238925",
      "Telephone": "66789485",
      "ConnectedTo": "Admin",
      "ConnectedToId": "123",
      "HSEManager": "Marina Magerøy",
      "BusinessContact": "Lars Andre Skogstad",
      "ContactMobile": "48499613",
      "BusinessContactTelephone": "45283769",
      "NoOfEmployees": "15",
      "Status": "Active",
      "ModifiedOn": "2016-10-01T23:55:01.033",
      "LicenseMonth": 10,
      "Category": "Godstransport på vei"
    },
  </code></pre>