Fix usage column error on 3.0 and lower servers (#587)

Author: durran

src/internal-packages/indexes/lib/component/usage-column.jsx

@@ -1,5 +1,10 @@
 const React = require('react');
 
+/**
+ * No usage stats constant.
+ */
+const NO_USAGE_STATS = 'Server versions prior to 3.2 do not support $indexStats';
+
 /**
  * Component for the usage column.
  */
@@ -14,6 +19,18 @@ class UsageColumn extends React.Component {
     super(props);
   }
 
+  /**
+   * Render the usage tooltip text.
+   *
+   * @returns {String} The tooltip.
+   */
+  tooltip() {
+    if (this.props.usage) {
+      return `${this.props.usage} index hits since index creation or last\n server restart`;
+    }
+    return NO_USAGE_STATS;
+  }
+
   /**
    * Render the usage column.
    *
@@ -23,13 +40,13 @@ class UsageColumn extends React.Component {
     return (
       <td className="usage-column">
         <span className="usage">
-          <div className="quantity" title={`${this.props.usage} index hits since index creation or last\n server restart`}>
-            {this.props.usage}
+          <div className="quantity" title={this.tooltip()}>
+            {this.props.usage || 'N/A'}
           </div>
           <div className="usage-since">
             since&nbsp;
             <span>
-              {this.props.since.toDateString()}
+              {this.props.since ? this.props.since.toDateString() : 'N/A'}
             </span>
           </div>
         </span>
@@ -41,8 +58,8 @@ class UsageColumn extends React.Component {
 UsageColumn.displayUsage = 'UsageColumn';
 
 UsageColumn.propTypes = {
-  usage: React.PropTypes.number.isRequired,
-  since: React.PropTypes.any.isRequired
+  usage: React.PropTypes.any,
+  since: React.PropTypes.any
 };
 
 module.exports = UsageColumn;