Angular：将JSON对象属性排除在过滤之外

Question

我正在使用此http://plnkr.co/edit/U1TOccm3pURetRTUul12?p=preview来搜索json格式的多个对象关键字。来自plunker的代码：

 angular
 .module('demo', [])
 .controller('ctrl', function ($scope) {

$scope.projects = [
  { id: 1, name: 'foo', keywords: 'aa bb cc' },
  { id: 2, name: 'bar', keywords: 'dd ee ff' },
  { id: 3, name: 'qux', lvl1: { lvl2: 'gg hh ii' } },
  { id: 4, name: 'baz', lvl1: { lvl2: { lvl3: 'gg hh ii' } } }
];

$scope.matchProject = function (project) {
  // Match all projects if no terms are entered
  if ($scope.searchText == null) return true;
  // Match project if all terms are matched
  var searchTerms = splitTerms($scope.searchText);
  var projectTerms = walkTerms(project);
  var unmatchedTerms = searchTerms.filter(function (searchTerm) {
    return projectTerms.filter(function (projectTerm) {
      return projectTerm.indexOf(searchTerm) !== -1;
    }).length === 0;
  });
  return unmatchedTerms.length === 0;
};

function walkTerms(obj, terms) {
  if (terms == null) {
    terms = [];
  }
  for (var key in obj) {
    // Ignore properties added by Angular
    if (key.startsWith('$$')) continue;
    // Ignore `null`, `undefined` or Array values
    if (obj[key] == null || obj[key].constructor === Array) continue;
    if (obj[key].constructor === Object) {
      walkTerms(obj[key], terms);
      continue;
    }
    if (typeof(obj[key]) === 'string') {
      Array.prototype.push.apply(terms, splitTerms(obj[key]));
      continue;
    }
    // Must be a boolean or number
    terms.push(obj[key].toString());
  }
  return terms;
}

function splitTerms(text) {
  if (text == null) return [];
  return text
    .toLowerCase()
    .split(/\s+/)
    .filter(function (term) {
      return term.length > 0;
    });
}

}）;

对我来说，

$scope.projects是一个项目对象列表。

$scope.projects = [
  { id: 1, name: 'foo', keywords: 'aa bb cc', image: //BLOB DATA HERE },
  { id: 2, name: 'bar', keywords: 'dd ee ff', image: //BLOB DATA HERE },
  { id: 3, name: 'qux', lvl1: { lvl2: 'gg hh ii' } },
  { id: 4, name: 'baz', lvl1: { lvl2: { lvl3: 'gg hh ii' } } }
 ];

我使用SQL查询获取对象并使用json_encode。我的一个对象键是MEDIUMBLOB。 ng-repeat过滤器因此属性（dupes和notArray错误）而出现故障。

有没有办法解决这个问题，例如：排除BLOB属性被搜索？如何在plunker中排除该特定键？