First public commit

utils/date-time-utils.ts

@@ -0,0 +1,100 @@
+import { format, isSameDay } from "date-fns";
+import { formatInTimeZone } from "date-fns-tz";
+import spacetime from "spacetime";
+
+import {
+  DateTimeOption,
+  TimeOption,
+} from "../components/forms/poll-options-form";
+
+export const getBrowserTimeZone = () =>
+  Intl.DateTimeFormat().resolvedOptions().timeZone;
+
+export const encodeDateOption = (option: DateTimeOption) => {
+  return option.type === "timeSlot"
+    ? `${option.start}/${option.end}`
+    : option.date;
+};
+
+type ParsedDateTimeOpton = { day: string; dow: string; month: string } & (
+  | {
+      type: "timeSlot";
+      startTime: string;
+      endTime: string;
+    }
+  | {
+      type: "date";
+    }
+);
+
+export const decodeDateOption = (
+  option: string,
+  timeZone: string | null,
+  targetTimeZone: string,
+): ParsedDateTimeOpton => {
+  const isTimeRange = option.indexOf("/") !== -1;
+  // option can either be an ISO date (ex. 2000-01-01)
+  // or a time range (ex. 2000-01-01T08:00:00/2000-01-01T09:00:00)
+  if (isTimeRange) {
+    const [start, end] = option.split("/");
+
+    if (timeZone && targetTimeZone) {
+      const startDate = spacetime(start, timeZone).toNativeDate();
+      const endDate = spacetime(end, timeZone).toNativeDate();
+      return {
+        type: "timeSlot",
+        startTime: formatInTimeZone(startDate, targetTimeZone, "hh:mm a"),
+        endTime: formatInTimeZone(endDate, targetTimeZone, "hh:mm a"),
+        day: formatInTimeZone(startDate, targetTimeZone, "dd"),
+        dow: formatInTimeZone(startDate, targetTimeZone, "E"),
+        month: formatInTimeZone(startDate, targetTimeZone, "MMM"),
+      };
+    } else {
+      const date = new Date(start);
+      return {
+        type: "timeSlot",
+        startTime: format(date, "hh:mm a"),
+        endTime: format(new Date(end), "hh:mm a"),
+        day: format(date, "dd"),
+        dow: format(date, "E"),
+        month: format(date, "MMM"),
+      };
+    }
+  }
+
+  // we add the time because otherwise Date will assume UTC time which might change the day for some time zones
+  const date = new Date(option + "T00:00:00");
+  return {
+    type: "date",
+    day: format(date, "dd"),
+    dow: format(date, "E"),
+    month: format(date, "MMM"),
+  };
+};
+
+export const removeAllOptionsForDay = (
+  options: DateTimeOption[],
+  date: Date,
+) => {
+  return options.filter((option) => {
+    const optionDate = spacetime(
+      option.type === "date" ? option.date : option.start,
+    ).toNativeDate();
+    return !isSameDay(date, optionDate);
+  });
+};
+
+export const getDateProps = (date: Date) => {
+  return {
+    day: format(date, "dd"),
+    dow: format(date, "E"),
+    month: format(date, "MMM"),
+  };
+};
+
+export const expectTimeOption = (d: DateTimeOption): TimeOption => {
+  if (d.type === "date") {
+    throw new Error("Expected timeSlot but got date instead");
+  }
+  return d;
+};