https://www.dotconferences.com/2016/10/dmitri-shuralyov-go-in-the-browser

streamingHttpResponseBodies.js

var query = 'gopher';
fetch('/large.csv').then(function(response) {
  var reader = response.body.getReader();
  var partialRecord = '';
  var decoder = new TextDecoder();
  
  function search() {
    return reader.read().then(function(result) {
      partialRecord += decoder.decodde(result.value || new Uint8Array, { stream: !result.done });
      // query logic...
      // Call reader.cancel('No more reading needed.'); when result found early.
      if (result.done) {
        throw Error('Count not find value after ' + query);
      }
      return search();
    });
  }
  return search();
}).then(function(result) {
  console.log('Got the result! It's "' + result + '"');
}).catch(function(err) {
  console.log(err.message);
});