Query and display weather data for all country

web/src/cities/helpers.ts

@@ -0,0 +1,47 @@
+import moment from "moment";
+
+export function formatDateString(str: string): string {
+    const date = moment(new Date(str));
+    switch (str.length) {
+      // year: 2023
+      case 4: return date.format("yyyy");
+      // year-month: 2023-06
+      case 7: return date.format("yyyy-MM");
+      // year-month-day: 2023-06-23
+      case 10: return date.format("yyyy-MM-DD");
+      // year-month-day hour:minute 2023-06-23T23:59
+      default: return date.format("HH:mm");
+    }
+}
+
+export interface QueryResult {
+    query: DataQuery;
+    result: {[key: string]: any};
+}
+
+export interface DataQuery {
+    cities: string[];
+    field: string;
+    granularity: string;
+    key: string;
+}
+
+export function isQueryResult(variable: any): variable is QueryResult {
+    return variable
+        && variable.query
+        && isDataQuery(variable.query)
+        && variable.result
+        && (
+            typeof variable.result === "object"
+            && !Array.isArray(variable.result)
+            && variable.result !== null
+        );
+}
+
+export function isDataQuery(variable: any): variable is DataQuery {
+  return variable && 
+      Array.isArray(variable.cities) && 
+      typeof variable.field === 'string' && 
+      typeof variable.granularity === 'string' &&
+      typeof variable.key === 'string';
+}