lastValue: defaults to current value to fix first animation

Author: antoinerg

src/traces/indicator/calc.js

@@ -14,7 +14,8 @@ function calc(gd, trace) {
     var cd = [];
 
     var lastReading = trace.value;
-    var secondLastReading = trace._lastValue || trace.value;
+    if(!(typeof trace._lastValue === 'number')) trace._lastValue = trace.value;
+    var secondLastReading = trace._lastValue;
     var deltaRef = secondLastReading;
     if(trace._hasDelta && typeof trace.delta.reference === 'number') {
         deltaRef = trace.delta.reference;

src/traces/indicator/plot.js

@@ -478,9 +478,10 @@ function drawAngularGauge(gd, plotGroup, cd, gaugeOpts) {
             .transition()
             .duration(transitionOpts.duration)
             .ease(transitionOpts.easing)
-            .each('end', function() { trace._lastValue = cd[0].y; onComplete && onComplete(); })
+            .each('end', function() { onComplete && onComplete(); })
             .each('interrupt', function() { onComplete && onComplete(); })
             .attrTween('d', arcTween(valueArcPathGenerator, valueToAngle(cd[0].lastY), valueToAngle(cd[0].y)));
+        trace._lastValue = cd[0].y;
     } else {
         valueArcPath
             .attr('d', valueArcPathGenerator.endAngle(valueToAngle(cd[0].y)));