It appears you have a well-structured Git repository with various files, including SVG icons and HTML documents. Here's a brief overview:

backend/node_modules/date-fns/differenceInCalendarDays/index.d.ts

@@ -0,0 +1,4 @@
+// This file is generated automatically by `scripts/build/typings.js`. Please, don't change it.
+
+import { differenceInCalendarDays } from 'date-fns'
+export default differenceInCalendarDays

backend/node_modules/date-fns/differenceInCalendarDays/index.js

@@ -0,0 +1,55 @@
+"use strict";
+
+var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault").default;
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = differenceInCalendarDays;
+var _index = _interopRequireDefault(require("../_lib/getTimezoneOffsetInMilliseconds/index.js"));
+var _index2 = _interopRequireDefault(require("../startOfDay/index.js"));
+var _index3 = _interopRequireDefault(require("../_lib/requiredArgs/index.js"));
+var MILLISECONDS_IN_DAY = 86400000;
+
+/**
+ * @name differenceInCalendarDays
+ * @category Day Helpers
+ * @summary Get the number of calendar days between the given dates.
+ *
+ * @description
+ * Get the number of calendar days between the given dates. This means that the times are removed
+ * from the dates and then the difference in days is calculated.
+ *
+ * @param {Date|Number} dateLeft - the later date
+ * @param {Date|Number} dateRight - the earlier date
+ * @returns {Number} the number of calendar days
+ * @throws {TypeError} 2 arguments required
+ *
+ * @example
+ * // How many calendar days are between
+ * // 2 July 2011 23:00:00 and 2 July 2012 00:00:00?
+ * const result = differenceInCalendarDays(
+ *   new Date(2012, 6, 2, 0, 0),
+ *   new Date(2011, 6, 2, 23, 0)
+ * )
+ * //=> 366
+ * // How many calendar days are between
+ * // 2 July 2011 23:59:00 and 3 July 2011 00:01:00?
+ * const result = differenceInCalendarDays(
+ *   new Date(2011, 6, 3, 0, 1),
+ *   new Date(2011, 6, 2, 23, 59)
+ * )
+ * //=> 1
+ */
+function differenceInCalendarDays(dirtyDateLeft, dirtyDateRight) {
+  (0, _index3.default)(2, arguments);
+  var startOfDayLeft = (0, _index2.default)(dirtyDateLeft);
+  var startOfDayRight = (0, _index2.default)(dirtyDateRight);
+  var timestampLeft = startOfDayLeft.getTime() - (0, _index.default)(startOfDayLeft);
+  var timestampRight = startOfDayRight.getTime() - (0, _index.default)(startOfDayRight);
+
+  // Round the number of days to the nearest integer
+  // because the number of milliseconds in a day is not constant
+  // (e.g. it's different in the day of the daylight saving time clock shift)
+  return Math.round((timestampLeft - timestampRight) / MILLISECONDS_IN_DAY);
+}
+module.exports = exports.default;

backend/node_modules/date-fns/differenceInCalendarDays/index.js.flow

@@ -0,0 +1,55 @@
+// @flow
+// This file is generated automatically by `scripts/build/typings.js`. Please, don't change it.
+
+export type Interval = {
+  start: Date | number,
+  end: Date | number,
+}
+
+export type Locale = {
+  code?: string,
+  formatDistance?: (...args: Array<any>) => any,
+  formatRelative?: (...args: Array<any>) => any,
+  localize?: {
+    ordinalNumber: (...args: Array<any>) => any,
+    era: (...args: Array<any>) => any,
+    quarter: (...args: Array<any>) => any,
+    month: (...args: Array<any>) => any,
+    day: (...args: Array<any>) => any,
+    dayPeriod: (...args: Array<any>) => any,
+  },
+  formatLong?: {
+    date: (...args: Array<any>) => any,
+    time: (...args: Array<any>) => any,
+    dateTime: (...args: Array<any>) => any,
+  },
+  match?: {
+    ordinalNumber: (...args: Array<any>) => any,
+    era: (...args: Array<any>) => any,
+    quarter: (...args: Array<any>) => any,
+    month: (...args: Array<any>) => any,
+    day: (...args: Array<any>) => any,
+    dayPeriod: (...args: Array<any>) => any,
+  },
+  options?: {
+    weekStartsOn?: 0 | 1 | 2 | 3 | 4 | 5 | 6,
+    firstWeekContainsDate?: 1 | 2 | 3 | 4 | 5 | 6 | 7,
+  },
+}
+
+export type Duration = {
+  years?: number,
+  months?: number,
+  weeks?: number,
+  days?: number,
+  hours?: number,
+  minutes?: number,
+  seconds?: number,
+}
+
+export type Day = 0 | 1 | 2 | 3 | 4 | 5 | 6
+
+declare module.exports: (
+  dateLeft: Date | number,
+  dateRight: Date | number
+) => number

backend/node_modules/date-fns/differenceInCalendarDays/package.json

@@ -0,0 +1,5 @@
+{
+  "sideEffects": false,
+  "module": "../esm/differenceInCalendarDays/index.js",
+  "typings": "../typings.d.ts"
+}