Question

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="blog">
  <div class="blogPost">
    <div class="postTitre">title</div>
    <div class="closeDelete">
      <input type="text" name="txtID" readonly="readonly" value="123" />X
      <div class="close-text">DELETE</div>
    </div>
  </div>
  <div class="blogPost">
    <div class="postTitre">title</div>
    <div class="closeDelete">
      <input type="text" name="txtID" readonly="readonly" value="342" />X
      <div class="close-text">DELETE</div>
    </div>
  </div>
  <div class="blogPost">
    <div class="postTitre">title</div>
    <div class="closeDelete">
      <input type="text" name="txtID" readonly="readonly" value="486" />X
      <div class="close-text">DELETE</div>
    </div>
  </div>
</div>

上面是我的代码，我的问题是，Specimen.find（{＆＃34; taxonomy.class＆＃34;：filter_spec}，它的工作原理。但是当放入文本时（＆＃34; taxonomy.class＆＃34;等等）在一个变量中，它不再起作用了。如果我不能完成这项工作，那将是非常低效的，因为我必须处理好几个案例。

Answer 1

如果要将object属性放在变量中，则需要使用 square bracket notation 来构造字段对象，如下所示：

var query = { },
    projection = {
        // Get only the taxonomy stuff
        "taxonomy.phylum": 1,
        "taxonomy.class": 1,
        "taxonomy.order": 1,
        "taxonomy.family": 1,
        "taxonomy.genus": 1,
        "taxonomy.species": 1,
        "common_name": 1,
        "last_edit": 1
    };

query[filter_fin] = filter_spec;
Specimen.find(query, projection, callback);

或使用computed property names (ES6)：

var query = { 
        [filter_fin]: filter_spec
    },
    projection = {
        // Get only the taxonomy stuff
        "taxonomy.phylum": 1,
        "taxonomy.class": 1,
        "taxonomy.order": 1,
        "taxonomy.family": 1,
        "taxonomy.genus": 1,
        "taxonomy.species": 1,
        "common_name": 1,
        "last_edit": 1
    };

Specimen.find(query, projection, callback);

MEAN STACK变量比较

1 个答案: