Show all combobox entries when clicking the caret (fixes #1755)

js/lib/d3.combobox.js

@@ -44,11 +44,12 @@ d3.combobox = function() {
                         d3.event.stopPropagation();
                         d3.event.preventDefault();
                         input.node().focus();
+                        fetch('', render);
                     });
             });
 
         function focus() {
-            fetch(render);
+            fetch(value(), render);
         }
 
         function blur() {
@@ -138,7 +139,7 @@ d3.combobox = function() {
         }
 
         function change() {
-            fetch(function() {
+            fetch(value(), function() {
                 autocomplete();
                 render();
             });
@@ -163,8 +164,8 @@ d3.combobox = function() {
             return value;
         }
 
-        function fetch(cb) {
-            fetcher.call(input, value(), function(_) {
+        function fetch(v, cb) {
+            fetcher.call(input, v, function(_) {
                 suggestions = _;
                 cb();
             });

test/spec/lib/d3.combobox.js

@@ -95,6 +95,13 @@ describe("d3.combobox", function() {
         expect(body.selectAll('.combobox-option').size()).to.equal(0);
     });
 
+    it("shows all entries when clicking on the caret", function() {
+        input.property('value', 'foo').call(combobox.data(data));
+        happen.mousedown(body.selectAll('.combobox-caret').node());
+        expect(body.selectAll('.combobox-option').size()).to.equal(3);
+        expect(body.selectAll('.combobox-option').text()).to.equal('foo');
+    });
+
     it("is initially shown with no selection", function() {
         input.call(combobox.data(data));
         input.node().focus();