DELETE request returns SyntaxError: Unexpected end of JSON input about keen-js HOT 4 CLOSED

import Keen from 'keen-js';

const client = new Keen({
  projectId: 'PROJECT_ID',
  masterKey: 'MASTER_KEY'
});

/*
  Filters and timeframe must be passed as encoded query string parameters. 
  This example constructs a complete URL to ensure the request is executed properly.
*/
const url = client.url('events', 'my-event-stream', {
  api_key: client.masterKey(),
  filters: encodeURIComponent(JSON.stringify([
    {
      property_name: 'user.id',
      operator: 'eq',
      property_value: 'f1243353243fdb'
    }
  ])),
  timeframe: encodeURIComponent(JSON.stringify({
    start: '2015-05-15T19:00:00.000Z',
    end: '2015-06-07T19:00:00.000Z'
  })),
  timezone: 'US/Pacific'
});

client
  .del(url)
  .send()
  .then(res => {
    // Handle response
  })
  .catch(err => {
    // Handle error
  });