[backport] PR #7123 to 4.6 - Honor custom label in percentile ranks aggregation

src/ui/public/agg_types/__tests__/metrics/percentile_ranks.js

@@ -0,0 +1,36 @@
+describe('AggTypeMetricPercentileRanksProvider class', function () {
+  let ngMock = require('ngMock');
+  let expect = require('expect.js');
+
+  let Vis;
+  let indexPattern;
+  let aggTypeMetricPercentileRanks;
+
+  beforeEach(ngMock.module('kibana'));
+  beforeEach(ngMock.inject(function (Private) {
+    Vis = Private(require('ui/Vis'));
+    indexPattern = Private(require('fixtures/stubbed_logstash_index_pattern'));
+    aggTypeMetricPercentileRanks = Private(require('ui/agg_types/metrics/percentile_ranks'));
+  }));
+
+  it('uses the custom label if it is set', function () {
+    const vis = new Vis(indexPattern, {});
+
+    // Grab the aggConfig off the vis (we don't actually use the vis for
+    // anything else)
+    const aggConfig = vis.aggs[0];
+    aggConfig.params.customLabel = 'my custom field label';
+    aggConfig.params.values = [ 5000, 10000 ];
+    aggConfig.params.field = {
+      displayName: 'bytes'
+    };
+
+    const responseAggs = aggTypeMetricPercentileRanks.getResponseAggs(aggConfig);
+    const percentileRankLabelFor5kBytes = responseAggs[0].makeLabel();
+    const percentileRankLabelFor10kBytes = responseAggs[1].makeLabel();
+
+    expect(percentileRankLabelFor5kBytes).to.be('Percentile rank 5,000 of "my custom field label"');
+    expect(percentileRankLabelFor10kBytes).to.be('Percentile rank 10,000 of "my custom field label"');
+  });
+
+});

src/ui/public/agg_types/metrics/percentile_ranks.js

@@ -14,8 +14,9 @@ define(function (require) {
       makeLabel: function () {
         let field = this.field();
         let format = (field && field.format) || fieldFormats.getDefaultInstance('number');
+        const label = this.params.customLabel || this.fieldDisplayName();
 
-        return 'Percentile rank ' + format.convert(this.key, 'text') + ' of "' + this.fieldDisplayName() + '"';
+        return 'Percentile rank ' + format.convert(this.key, 'text') + ' of "' + label + '"';
       }
     };