Continuity: Fix TTFI when EventTiming plugin is missing

Author: nicjansma

plugins/continuity.js

@@ -3835,7 +3835,7 @@
      * Analyzes Interactions
      */
     function analyze(startTime) {
-      var fid;
+      var fid, ttfi, ET;
 
       impl.addToBeacon("c.i.dc", externalMetrics.interactionDelayed());
       impl.addToBeacon("c.i.dt", externalMetrics.interactionDelayedTime());
@@ -3844,20 +3844,25 @@
       // Only send FID and TTFI Timers once
       if (!sentTimers) {
         // defer to EventTiming's FID if available
-        if (BOOMR.plugins.EventTiming &&
-            BOOMR.plugins.EventTiming.is_enabled()) {
-          fid = BOOMR.plugins.EventTiming.metrics.firstInputDelay();
+        ET = BOOMR.plugins.EventTiming;
+
+        if (ET && ET.is_enabled()) {
+          fid = ET.metrics.firstInputDelay();
+          ttfi = ET.metrics.timeToFirstInteraction();
         }
 
         if (!fid && firstInputDelay !== null) {
           fid = externalMetrics.firstInputDelay();
         }
 
+        if (!ttfi) {
+          ttfi = externalMetrics.timeToFirstInteraction();
+        }
+
         if (typeof fid === "number") {
           impl.addToBeacon("c.fid", Math.ceil(fid), true);
 
-          impl.addToBeacon("c.ttfi",
-            BOOMR.plugins.EventTiming.metrics.timeToFirstInteraction() || externalMetrics.timeToFirstInteraction());
+          impl.addToBeacon("c.ttfi", ttfi, true);
 
           sentTimers = true;
         }

tests/page-templates/21-continuity/49-interaction-no-eventtiming.html

@@ -0,0 +1,44 @@
+<%= header %>
+<!--
+Same as 13-interaction but without the EventTiming plugin
+-->
+<%= boomerangScript %>
+<p>45-interaction-no-eventtiming loading...</p>
+<script src="49-interaction-no-eventtiming.js" type="text/javascript"></script>
+<script>
+// test that `c.ttfi` can be set without the EventTiming plugin
+delete BOOMR.plugins.EventTiming;
+
+BOOMR_test.init({
+  testAfterOnBeacon: true,
+  Continuity: {
+    enabled: true
+  }
+});
+
+try {
+  // the event timestamp is set when the object is created
+  var ev = document.createEvent("Event");
+
+  ev.initEvent("keydown", true, true);
+  ev.keyCode = 27;
+}
+catch (e) {
+  window.cannotCreateMouseEvent = true;
+}
+
+// click
+window.ttfi = BOOMR.now();
+
+// dispatch event is synchronous. Wait 20ms between the event creation and dispatch
+BOOMR_test.busy(20);
+document.dispatchEvent(ev);
+
+setTimeout(function() {
+  // click key again
+  document.dispatchEvent(ev);
+  document.dispatchEvent(ev);
+}, 250);
+</script>
+<img src="/delay?delay=3000&amp;file=assets/img.jpg" width="200" height="10000" />
+<%= footer %>

tests/page-templates/21-continuity/49-interaction-no-eventtiming.js

@@ -0,0 +1,65 @@
+/* eslint-env mocha */
+/* global BOOMR_test,assert */
+
+describe("e2e/21-continuity/49-interaction-no-eventtiming", function() {
+  var tf = BOOMR.plugins.TestFramework;
+  var t = BOOMR_test;
+
+  it("Should have sent a single beacon validation", function(done) {
+    t.validateBeaconWasSent(done);
+  });
+
+  it("Should not have the EventTiming plugin", function(done) {
+    assert.isUndefined(BOOMR.plugins.EventTiming);
+  });
+
+  it("Should have sent the Time to First Interaction (c.ttfi)", function() {
+    var b = tf.lastBeacon();
+
+    assert.isDefined(b["c.ttfi"]);
+    var ttfi = parseInt(b["c.ttfi"], 10);
+
+    if (t.isNavigationTimingSupported()) {
+      var st = parseInt(b["rt.tstart"], 10);
+
+      assert.closeTo(st + ttfi, window.ttfi, 20);
+    }
+    else {
+      assert.operator(ttfi, ">=", 0);
+    }
+  });
+
+  it("Should have the interaction timeline (c.t.inter)", function() {
+    var b = tf.lastBeacon();
+
+    assert.isDefined(b["c.t.inter"]);
+    assert.operator(b["c.t.inter"].length, ">=", 1);
+  });
+
+  it("Could have the interaction delay timeline (c.t.interdly)", function() {
+    var b = tf.lastBeacon();
+
+    if (b["c.i.a"]) {
+      assert.isDefined(b["c.t.interdly"]);
+      assert.operator(b["c.t.interdly"].length, ">=", 1);
+    }
+  });
+
+  it("Could have interaction delay metrics (c.i.a, c.i.dc and c.i.dt)", function() {
+    var b = tf.lastBeacon();
+
+    if (!b["c.i.a"]) {
+      assert.operator(parseInt(b["c.i.a"], 10), ">=", 1);
+      assert.operator(parseInt(b["c.i.dc"], 10), ">=", 1);
+      assert.operator(parseInt(b["c.i.dc"], 10), "<=", 10);
+      assert.operator(parseInt(b["c.i.dt"], 10), ">=", 1);
+    }
+  });
+
+  it("Should have First Input Delay (c.fid)", function() {
+    var b = tf.lastBeacon();
+
+    assert.isDefined(b["c.fid"]);
+    assert.operator(parseInt(b["c.fid"], 10), ">=", 19); // we had a 20ms busy wait, allow for some fuzzing
+  });
+});