add a function that returns a valid date last purchased or a valid da…

…te created; propose a function that will calculate days form passed in date to today; pass the latter into firebase

src/api/firebase.js

@@ -10,7 +10,7 @@ import {
 } from 'firebase/firestore';
 import { useEffect, useState } from 'react';
 import { db } from './config';
-import { addDaysFromToday, getDaysBetweenDates } from '../utils';
+import { addDaysFromToday, getDaysFromDate } from '../utils';
 
 /**
  * A custom hook that subscribes to the user's shopping lists in our Firestore

src/utils/dates.js

@@ -51,12 +51,30 @@ export const calculateDateNextPurchased = (currentDate, item) => {
  * @param {Date} laterDate The ending date.
  * @returns {number} The number of days between the two dates.
  */
-function getDaysBetweenDates(earlierDate, laterDate) {
+export function getDaysBetweenDates(earlierDate, laterDate) {
 	return Math.floor(
 		(laterDate.getTime() - earlierDate.getTime()) / ONE_DAY_IN_MILLISECONDS,
 	);
 }
 
+// takes in a Date
+// calculates days since date that was passed and today
+export const getDaysFromDate = (pastDate) => {
+	const today = new Date();
+	const daysToToday = getDaysBetweenDates(pastDate, today);
+	return daysToToday;
+};
+
+// takes in Timestamps, returns a Date
+export const getDateLastPurchasedOrDateCreated = (
+	dateLastPurchased,
+	dateCreated,
+) => {
+	const lastPurchaseDate = dateLastPurchased?.toDate();
+	// console.log(lastPurchaseDate ?? dateCreated.toDate(), 'returning this from long name func');
+	return lastPurchaseDate ?? dateCreated.toDate();
+};
+
 /**
  * Calculate the purchase intervals between current, next, and last purchase dates.
  * @param {Date} currentDate The current date.
@@ -70,20 +88,20 @@ function calculatePurchaseIntervals(
 	dateNextPurchased,
 	dateLastPurchased,
 ) {
-	const lastPurchaseDate = dateLastPurchased?.toDate();
-
-	const lastEstimatedIntervalStartDate =
-		lastPurchaseDate ?? dateCreated.toDate();
+	const lastEstimatedIntervalStartDate = getDateLastPurchasedOrDateCreated(
+		dateLastPurchased,
+		dateCreated,
+	);
 
 	const lastEstimatedInterval = getDaysBetweenDates(
 		lastEstimatedIntervalStartDate,
 		dateNextPurchased.toDate(),
 	);
 
 	const daysSinceLastPurchase =
-		lastPurchaseDate === undefined
+		dateLastPurchased?.toDate() === undefined
 			? 0
-			: getDaysBetweenDates(lastPurchaseDate, currentDate);
+			: getDaysBetweenDates(dateLastPurchased.toDate(), currentDate);
 
 	return { lastEstimatedInterval, daysSinceLastPurchase };
 }