How do I read binary data to a byte array in Javascript?

I want to read a binary file in JavaScript that would be gotten through XMLHttpRequest and be able to manipulate that data. From my researching I discovered this method of reading a binary file data into an array

var xhr = new XMLHttpRequest();
xhr.open('GET', '/binary_And_Ascii_File.obj', true);

xhr.responseType = 'arraybuffer';

xhr.onload = function(e) {
  var uInt8Array = new Uint8Array(this.response);
};

How do I convert this binary data array to a human-readable-string?