Default hovermode to closest if clickmode is select [1852]

Author: rmoestl

src/components/fx/layout_attributes.js

@@ -59,7 +59,16 @@ module.exports = {
         role: 'info',
         values: ['x', 'y', 'closest', false],
         editType: 'modebar',
-        description: 'Determines the mode of hover interactions.'
+        description: [
+            'Determines the mode of hover interactions.',
+            'If `clickmode` includes the *select* flag,',
+            '`hovermode` defaults to *closest*.',
+            'If `clickmode` lacks the *select* flag,',
+            'it defaults to *x* or *y* (depending on the trace\'s',
+            '`orientation` value) for plots based on',
+            'cartesian coordinates. For anything else the default',
+            'value is *closest*.',
+        ].join(' ')
     },
     hoverdistance: {
         valType: 'integer',

src/components/fx/layout_defaults.js

@@ -23,10 +23,14 @@ module.exports = function supplyLayoutDefaults(layoutIn, layoutOut, fullData) {
 
     var hovermodeDflt;
     if(layoutOut._has('cartesian')) {
-        // flag for 'horizontal' plots:
-        // determines the state of the mode bar 'compare' hovermode button
-        layoutOut._isHoriz = isHoriz(fullData);
-        hovermodeDflt = layoutOut._isHoriz ? 'y' : 'x';
+        if(layoutOut.clickmode.indexOf('select') > -1) {
+            hovermodeDflt = 'closest';
+        } else {
+            // flag for 'horizontal' plots:
+            // determines the state of the mode bar 'compare' hovermode button
+            layoutOut._isHoriz = isHoriz(fullData);
+            hovermodeDflt = layoutOut._isHoriz ? 'y' : 'x';
+        }
     }
     else hovermodeDflt = 'closest';
 

test/jasmine/tests/hover_label_test.js

@@ -2369,3 +2369,52 @@ describe('hover distance', function() {
         });
     });
 });
+
+describe('hovermode defaults to', function() {
+    var gd;
+
+    beforeEach(function() {
+        gd = createGraphDiv();
+    });
+
+    afterEach(destroyGraphDiv);
+
+    it('\'closest\' for cartesian plots if clickmode includes \'select\'', function(done) {
+        Plotly.plot(gd, [{ x: [1, 2, 3], y: [4, 5, 6] }], { clickmode: 'event+select' })
+          .then(function() {
+              expect(gd._fullLayout.hovermode).toBe('closest');
+          })
+          .catch(failTest)
+          .then(done);
+    });
+
+    it('\'x\' for horizontal cartesian plots if clickmode lacks \'select\'', function(done) {
+        Plotly.plot(gd, [{ x: [1, 2, 3], y: [4, 5, 6], type: 'bar', orientation: 'h' }], { clickmode: 'event' })
+          .then(function() {
+              expect(gd._fullLayout.hovermode).toBe('y');
+          })
+          .catch(failTest)
+          .then(done);
+    });
+
+    it('\'y\' for vertical cartesian plots if clickmode lacks \'select\'', function(done) {
+        Plotly.plot(gd, [{ x: [1, 2, 3], y: [4, 5, 6], type: 'bar', orientation: 'v' }], { clickmode: 'event' })
+          .then(function() {
+              expect(gd._fullLayout.hovermode).toBe('x');
+          })
+          .catch(failTest)
+          .then(done);
+    });
+
+    it('\'closest\' for a non-cartesian plot', function(done) {
+        var mock = require('@mocks/polar_scatter.json');
+        expect(mock.layout.hovermode).toBeUndefined();
+
+        Plotly.plot(gd, mock.data, mock.layout)
+          .then(function() {
+              expect(gd._fullLayout.hovermode).toBe('closest');
+          })
+          .catch(failTest)
+          .then(done);
+    });
+});