title: Extract all values for a single key in a js array of objects
body: <p>I have a json collection of objects</p>
  
  <pre><code>{  
     "images":{  
        "1":{  
           "image_data":{  
              "votable":true,
              "hashed_filename":"d66f00cf58c4fbbbc9703efff9c7694c"
           },
           "image_reference":1
        },
        "2":{  
           "image_data":{  
              "votable":true,
              "hashed_filename":"5485a21d47e3815cd7f23d5f8a8c8677"
           },
           "image_reference":2
        },
        "3":{  
           "image_data":{  
              "votable":true,
              "hashed_filename":"4df10b887f12d65f2f541c99f0dd1ef8"
           },
           "image_reference":3
        }
     }
  }
  </code></pre>
  
  <p>Is there an easy way to extract the hashed_filename value in a string separated by underscore?</p>
  
  <p>I need a result like <code>d66f00cf58c4fbbbc9703efff9c7694c_5485a21d47e3815cd7f23d5f8a8c8677_4df10b887f12d65f2f541c99f0dd1ef8</code></p>