prettier: change to single quoting

public/app/plugins/datasource/mixed/datasource.ts

@@ -1,17 +1,17 @@
 ///<reference path="../../../headers/common.d.ts" />
 
-import angular from "angular";
-import _ from "lodash";
+import angular from 'angular';
+import _ from 'lodash';
 
 class MixedDatasource {
   /** @ngInject */
   constructor(private $q, private datasourceSrv) {}
 
   query(options) {
-    var sets = _.groupBy(options.targets, "datasource");
+    var sets = _.groupBy(options.targets, 'datasource');
     var promises = _.map(sets, targets => {
       var dsName = targets[0].datasource;
-      if (dsName === "-- Mixed --") {
+      if (dsName === '-- Mixed --') {
         return this.$q([]);
       }
 
@@ -23,7 +23,7 @@ class MixedDatasource {
     });
 
     return this.$q.all(promises).then(function(results) {
-      return { data: _.flatten(_.map(results, "data")) };
+      return { data: _.flatten(_.map(results, 'data')) };
     });
   }
 }

public/app/plugins/datasource/mixed/module.ts

@@ -1,4 +1,4 @@
 ///<reference path="../../../headers/common.d.ts" />
 
-import { MixedDatasource } from "./datasource";
+import { MixedDatasource } from './datasource';
 export { MixedDatasource, MixedDatasource as Datasource };