<input type="file" onchange="angular.element(this).scope().onFileChange(this)">

$scope.onFileChange = function (fileEl) {
  var files = fileEl.files;
  var file = files[0];
  var reader = new FileReader();

  reader.onloadend = function(evt) {
    if (evt.target.readyState === FileReader.DONE) {
      $scope.$apply(function () {
        $scope.something = JSON.parse(evt.target.result);
      });
    }
  };

  reader.readAsText(file);
};