fix3710 - format waterfall values and sums in hover

Author: archmoj

src/traces/waterfall/hover.js

@@ -16,6 +16,10 @@ var DIRSYMBOL = {
     decreasing: '▼'
 };
 
+function formatNumber(a) {
+    return parseFloat(a.toPrecision(10));
+}
+
 module.exports = function hoverPoints(pointData, xval, yval, hovermode) {
     var point = hoverOnBars(pointData, xval, yval, hovermode);
     if(!point) return;
@@ -34,16 +38,16 @@ module.exports = function hoverPoints(pointData, xval, yval, hovermode) {
     if(!di.isSum) {
         // format delta numbers:
         if(size > 0) {
-            point.extraText = size + ' ' + DIRSYMBOL.increasing;
+            point.extraText = formatNumber(size) + ' ' + DIRSYMBOL.increasing;
         } else if(size < 0) {
-            point.extraText = '(' + (-size) + ') ' + DIRSYMBOL.decreasing;
+            point.extraText = '(' + (formatNumber(-size)) + ') ' + DIRSYMBOL.decreasing;
         } else {
             return;
         }
         // display initial value
-        point.extraText += '<br>Initial: ' + (di.b + di.s - size);
+        point.extraText += '<br>Initial: ' + formatNumber(di.b + di.s - size);
     } else {
-        point[sizeLetter + 'LabelVal'] = size;
+        point[sizeLetter + 'LabelVal'] = formatNumber(size);
     }
 
     point.color = getTraceColor(trace, di);

test/jasmine/tests/waterfall_test.js

@@ -1289,6 +1289,34 @@ describe('waterfall hover', function() {
             .catch(failTest)
             .then(done);
         });
+
+        describe('round hover precision', function() {
+            it('should format numbers', function(done) {
+                gd = createGraphDiv();
+
+                Plotly.plot(gd, {
+                    data: [{
+                        x: [1, 2, 3, 4, 5],
+                        y: [0, -1.1, 2.2, -3.3, 4.4],
+                        type: 'waterfall'
+                    }],
+                    layout: {width: 400, height: 400}
+                })
+                .then(function() {
+                    var evt = { xpx: 200, ypx: 350 };
+                    Fx.hover('graph', evt, 'xy');
+                })
+                .then(function() {
+                    assertHoverLabelContent({
+                        nums: '2.2\n4.4 ▲\nInitial: -2.2',
+                        name: '',
+                        axis: '5'
+                    });
+                })
+                .catch(failTest)
+                .then(done);
+            });
+        });
     });
 
     describe('with special width/offset combinations', function() {