Accessing data through names defined in capabilities.json

 I'll try to explain this the best I can.

If I have the following capabilities.json file:

{
  "dataRoles": [
    {
      "displayName": "Test 1",
      "name": "test1",
      "kind": "Grouping"
    },
    {
      "displayName": "Test 2",
      "name": "test2",
      "kind": "Grouping"
    }
  ],
  "dataViewMappings": [
    {
      "table": {
        "rows": {
          "select": [
            {
              "for": {
                "in": "test1"
              }
            },
            {
              "for": {
                "in": "test2"
              }
            }
          ]
        }
      }
    }
  ]
}

and in my dataset I have columns "foo" and "bar", then on my custom visual I can drag the foo column into the "Test 1" field, and the bar column into the "Test 2" field.

However, when I view the resulting dataset with console.log(options.dataViews[0].table), I don't see any mention of the words test1 and test2, only foo and bar... But these names are defined by the user, so they aren't much use to me!

At first I thought the columns might be ordered in the way they're defined in capabilities.json, so for example the first test1 item would be at options.dataViews[0].table.rows[0][0] and the first test2 item would be at options.dataViews[0].table.rows[0][1]... but there doesn't actually appear to be any particular order to the columns, so I can't rely on that method.

If I'm not being clear here, the following question is pretty much equivalent: how would I loop through every row in the table and output only the values corresponding to test1?