convert string to datetime  in javascript

You mean this?
Expected format: 2019-11-04T17:30:00+02:00 - but I expect +01:00 since it is not DST

https://jsfiddle.net/mplungjan/ot0xmh9s/

const pad = num => ("0" + num).slice(-2);

const getFormattedDate = d => {
  const tzOffsetMin = d.getTimezoneOffset(),
    offsetHours = Math.floor(Math.abs(tzOffsetMin / 60)),
    offsetMin = Math.abs(tzOffsetMin % 60);
  let sign = "";
  if (tzOffsetMin < 0) sign = "+"; // opposite of what we should think
  else if (tzOffsetMin > 0) sign = "-";

  // we could steal the time from the toString and replace / GMT/,""

  return `${d.getFullYear()}-${pad(d.getMonth()+1)}-${pad(d.getDate())}` +
    `T${pad(d.getHours())}:${pad(d.getMinutes())}:${pad(d.getSeconds())}` +
    `${sign}${pad(offsetHours)}:${pad(offsetMin)}${sign===""?"Z":""}`;
}

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Please see my updated answer.
I have written a function instead.
I still expect +01:00 and not +02:00 in Amsterdam in November

something more global and not specific

That +02:00 is your original post is specific to YOUR timezone
What I post is the UTC + 00:00 : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toISOString
You want +02:00 ?

a = new Date("11/04/2019 17:30:00");
a.setHours(a.getHours() + 2);
var d = a.toISOString().split(".")[0] + "+02:00"

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That would fail across daylight saving

Hi Pamela

Great you found a solution you could use.

But you did not actually use the answer you accepted as solution?