Where is the popularFields be assigned value, i do not found it:

[whoami]

I read a source code in kibana:

  <ul
    ng-show="(popularFields | filter:filter.isFieldFiltered).length > 0"
    ng-class="{ 'hidden-sm': !showFields, 'hidden-xs': !showFields }"
    class="list-unstyled sidebar-well discover-popular-fields">
    <li class="sidebar-item sidebar-list-header">
      <h6>Popular</h6>
    </li>
    <discover-field
      ng-repeat="field in popularFields | filter:filter.isFieldFiltered"
      field="field"
      on-add-field="onAddField"
      on-add-filter="onAddFilter"
      on-remove-field="onRemoveField"
      on-show-details="computeDetails"
    >
    </discover-field>
  </ul>

where is the popularFields be assigned value, i do not found it:

➜   grep popularFields -r .
./core_plugins/kibana/public/discover/components/field_chooser/field_chooser.html:    ng-show="(popularFields | filter:filter.isFieldFiltered).length > 0"
./core_plugins/kibana/public/discover/components/field_chooser/field_chooser.html:      ng-repeat="field in popularFields | filter:filter.isFieldFiltered"
./core_plugins/kibana/public/discover/components/field_chooser/field_chooser.html:      ng-repeat="field in unpopularFields | filter:filter.isFieldFiltered"

[tylersmalley]

Sadly, this is happening here: https://github.com/elastic/kibana/blob/master/src/core_plugins/kibana/public/discover/components/field_chooser/field_chooser.js#L145

[whoami]

hmm.., thank you guys.