templating: allow whitespace values

closes #7382

public/app/features/templating/query_variable.ts

@@ -140,8 +140,13 @@ export class QueryVariable implements Variable {
     }
     for (i = 0; i < metricNames.length; i++) {
       var item = metricNames[i];
-      var value = item.value || item.text;
-      var text = item.text || item.value;
+      var text = item.text === undefined || item.text === null
+        ? item.value
+        : item.text;
+
+      var value = item.value === undefined || item.value === null
+        ? item.text
+        : item.value;
 
       if (_.isNumber(value)) {
         value = value.toString();
@@ -178,7 +183,7 @@ export class QueryVariable implements Variable {
     if (sortType === 1) {
       options = _.sortBy(options, 'text');
     } else if (sortType === 2) {
-      options = _.sortBy(options, function(opt) {
+      options = _.sortBy(options, (opt) => {
         var matches = opt.text.match(/.*?(\d+).*/);
         if (!matches || matches.length < 2) {
           return -1;

public/app/features/templating/specs/query_variable_specs.ts

@@ -51,20 +51,23 @@ describe('QueryVariable', () => {
       var input = [
         {text: '0', value: '0'},
         {text: '1', value: '1'},
-        {text: '', value: ''},
         {text: null, value: 3},
         {text: undefined, value: 4},
         {text: '5', value: null},
         {text: '6', value: undefined},
-        {text: null, value: '3'},
-        {text: undefined, value: '4'},
-        {text: 5, value: null},
-        {text: 6, value: undefined},
+        {text: null, value: '7'},
+        {text: undefined, value: '8'},
+        {text: 9, value: null},
+        {text: 10, value: undefined},
+        {text: '', value: undefined},
+        {text: undefined, value: ''},
       ];
 
       var result = variable.metricNamesToVariableValues(input);
       it('should return in same order', () => {
         var i = 0;
+
+        expect(result.length).to.be(11);
         expect(result[i++].text).to.be('');
         expect(result[i++].text).to.be('0');
         expect(result[i++].text).to.be('1');