backend/service/RESTService.js
function(url, data) {
    let request = parseRequest(url, data);
    let resource = getRequestedResource(request);
    return resource.put(request)
      .then(returnResponse);

    function returnResponse(result) { // eslint-disable-line require-jsdoc
      return new RESTResponse(url, "PUT", result);
    }
  }
function(url, data) {
    let request = parseRequest(url, data);
    let resource = getRequestedResource(request);
    return resource.put(request)
      .then(returnResponse);

    function returnResponse(result) { // eslint-disable-line require-jsdoc
      return new RESTResponse(url, "PUT", result);
    }
  }
Handle PUT request.
@param {string} url - Resource locator.
@param {Object} data - Resource data.
@return {Promise} Updated resource.