fecth post json

(async () => {
  const rawResponse = await fetch('https://httpbin.org/post', {
    method: 'POST',
    headers: {
      'Accept': 'application/json',
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({a: 1, b: 'Textual content'})
  });
  const content = await rawResponse.json();

  console.log(content);
})();

var myHeaders = new Headers();

var myInit = { method: 'POST',
               headers: myHeaders,
               mode: 'cors',
               cache: 'default' };

fetch('flowers.jpg',myInit)
.then(function(response) {
  return response.blob();
})
.then(function(myBlob) {
  var objectURL = URL.createObjectURL(myBlob);
  myImage.src = objectURL;
});