Use best_run_id to determine start date on frontend; bring back next_run/date #2702

mbertrand · 2025-11-14T17:38:07Z

Depends on #2696

What are the relevant tickets?

Closes https://github.com/mitodl/hq/issues/9206

Description (What does it do?)

Refactors the frontend to use best_run_id for determining what start date to display if any
Brings back next_run property and assigns next_start_date based on that (only used for search purposes now).

How can this be tested?

Run recreate_index --all
Run all the course/program backpopulate commands (xpro, mit_edx, mitxonline, oll, sloan, mitpe)
Run learning_resources.tasks.update_next_start_date_and_prices() in a shell.
Check search results and drawers:
- All OCW and OLL courses should show "Starts: Anytime" in search results and course drawers
- Other courses should show either a future start date or today depending on what their best run is. For example:
  - http://open.odl.local:8062/search?platform=xpro&q=%22Applying+Machine+Learning%22 - should show today's date
  - http://open.odl.local:8062/search?platform=xpro&q=%22Quantum+Computing+Algorithms+for+Cybersecurity%22: should show March 09, 2026

ChristopherChudzicki

As written, I don't think this affects the DifferingRunsTable. Left a suggestion about how it could be done to affect that and deal with a date ordering issue.

ChristopherChudzicki · 2025-11-18T20:00:51Z

frontends/ol-utilities/src/learning-resources/pricing.ts

+    bestStart =
+      Date.parse(bestRun.start_date) > Date.parse(bestRun.enrollment_start)
+        ? bestRun.start_date
+        : bestRun.enrollment_start


The fallback here would be highly unexpected / bad data, right?

I just checked prod with

from learning_resources.models import LearningResourceRun from django.db.models import F # Filter runs where enrollment_start is greater than start_date (both fields must be non-null) runs = LearningResourceRun.objects.filter( enrollment_start__isnull=False, start_date__isnull=False, enrollment_start__gt=F('start_date') )

and runs.count() was 0. (RC did have 6 such runs, 1 of which was published. It was from MITxOnline. RC MITxOnline data is ...not great, though).

Suggestion: My inclination would be to leave a comment here that this is pretty unexpected.

Right, something would have to be quite wrong for a published course not to have a best run. I'll add a comment

ChristopherChudzicki · 2025-11-18T20:13:06Z

frontends/main/src/page-components/LearningResourceExpanded/InfoSection.tsx

+  if (sortedDates && bestStartDate && !anytime) {
+    // Replace the first date with best_start_date
+    sortedDates = [bestStartDate, ...sortedDates.slice(1)]


The original logic was incorrect here, I think. As currently structured, only "bestStartDate" has the possibility of being <current date>.

But sometimes the best run isn't the first run, so this ends up

// Resource 1, run start dates: Oc 31 2024 Oct 31 2025 Oct 31 2026 ↑ replaced by <current date> // Resource 2, run start dates: Oct 31 2025 Oct 31 2026 ↑ replaced by <current date>

As currently written, Resource 1 would display (using Nov 18 as current date):

// Resource 1, displayed value (current) Nov 18 2025 Oct 31 2025 Oct 31 2026 // Resource 1, displayed value (desired) Oct 31 2025 Nov 18 2025 Oct 31 2026

https://learn.mit.edu/search?platform=mitxonline&q=Minds+and+Machines&sortby=upcoming&resource=2810 is a similar example, where the first date is being replaced, but it should be the third. (Click "Show more")

My suggestion is: move the "maybe show current date" logic into formatRunDate. (Maybe rename to runDisplayDate or something?) That way:

the dates show up in correct order

Automatically affects DifferingRunsTable, too. (Which is displayed when runs are sufficiently different that the drawer shows a table, one row per run. Mostly relevant to SEE courses, I think?)

If ☝️ makes sense / sounds good, two things worth mentioning:

I think you would need to update LearningResourceCard / LearningResourceListCard to use startDate = formatRunDate(runs.find(best_run))

In LearningResourceCard / LearningResourceListCard, probably need to use NoSSR instead of LocalDate, since it will be formatted by the parent component, now.

ChristopherChudzicki · 2025-11-18T20:31:27Z

frontends/main/src/page-components/LearningResourceExpanded/InfoSection.test.tsx

+const daysFromToday = (days: number): string => {
+  const date = new Date()
+  date.setDate(date.getDate() + days)
+  return date.toISOString()
+}


mentioning... faker.date.soon({ days: <x-number> }) which creates a date 0–x days in the future, iirc.

I don't think it's what you wanted here, but might be useful some other time.

ChristopherChudzicki

👍 Working well.

I did leave one comment about potential shared logic. At the very least, I do think we should try and put those funcs in the same file. If we just move the func, I don't think we need to re-review, htough I'm happy to look again.

ChristopherChudzicki · 2025-11-21T20:38:06Z

frontends/ol-utilities/src/learning-resources/learning-resources.ts

    }
  }
+
+  // For the best run in dated resources, use special logic


I'm not sure the logic needs to be special... if a dated course had two active runs, I guess we could show the current date for both of those. You could "start today" for either run.

But I think that would be highly unexpected, so this is fine. 👍

This function is being applied to every run in a course. It's possible that a course might have 2 runs with past start dates, but only 1 is the "best" run, and my assumption was that's the only one that should show today's date, and any other non-best run with a start date in the past should show that past date?

PS an example of this is here: https://learn.mit.edu/search?q=%22Paradox+and+Infinity%22&resource=2809

two published runs:
run 1 (not best): "start_date": "2023-11-09T16:00:00Z"
run 2 (best): "start_date": "2025-02-04T16:00:00Z",

With this PR, InfoSection will show:

Starts:
November 09, 2023|November 24, 2025

Yeah, let's stick with your approach 👍

ChristopherChudzicki · 2025-11-22T01:20:26Z

frontends/ol-utilities/src/learning-resources/learning-resources.ts

+  if (run.id === bestRunId && availability === "dated" && !asTaughtIn) {
+    if (!run.start_date && !run.enrollment_start) return null
+
+    // Get the max of start_date and enrollment_start
+    let bestStart: string
+    if (run.start_date && run.enrollment_start) {
+      bestStart =
+        Date.parse(run.start_date) > Date.parse(run.enrollment_start)
+          ? run.start_date
+          : run.enrollment_start
+    } else {
+      bestStart = (run.start_date || run.enrollment_start)!
+    }
+
+    // If the best start date is in the future, show it; otherwise show today
+    const now = new Date()
+    const bestStartDate = new Date(bestStart)
+    if (bestStartDate > now) {
+      return formatDate(bestStart, "MMMM DD, YYYY")
+    } else {
+      return formatDate(new Date().toISOString(), "MMMM DD, YYYY")
+    }
+  }


The date determination is the same logic as getBestResourceStartDate, right? (This function formats it, too).

It would be great if we could share that logic. If not, maybe we could at least co-locate the two funcs in the same file. Odd that getBestResourceStartDate (and its predecessor, getResourceDate) are in the pricing.ts file.

getBestResourceStartDate (formerly bestStartDate takes in a resource as an input parameter, and returns the date of the best run, in ISO string format, Used in the resource cards,

formatRunDate takes in a run as an input parameter, and is called on every run for a resource. It returns the date in a string format that is dependent on certain attributes like semester, year, asTaughtIn boolean, and now also availablity and whether or not it is the best run (because today's date should be shown for a past date only for the best run, not other runs, or at least I presumed that). It is used in the InfoSection component and DifferingRunsTable.

I could adjust getBestResourceStartDate to call formatRunDate(best_run, showStartAnytime(resource), resource.availability, best_run.id) but I was hesitant to do that because of the differences in how that function formats the date outputs, which I assume was intentional?

Yeah, I think we'd have to extract the date-picking without formatting, which might not be trivial.

Let's keep as-is, but i do think co-locating the functions would be worthwhile.

mbertrand added the Needs Review An open Pull Request that is ready for review label Nov 14, 2025

ChristopherChudzicki self-requested a review November 14, 2025 20:16

ChristopherChudzicki self-assigned this Nov 14, 2025

ChristopherChudzicki requested changes Nov 18, 2025

View reviewed changes

ChristopherChudzicki added Waiting on author and removed Needs Review An open Pull Request that is ready for review labels Nov 18, 2025

mbertrand force-pushed the mb/next_start_date branch from 542ba39 to 7365408 Compare November 19, 2025 18:12

mbertrand force-pushed the mb/next_start_date_2 branch from f9edaed to 75462fb Compare November 19, 2025 20:54

Base automatically changed from mb/next_start_date to main November 20, 2025 13:33

mbertrand added 6 commits November 20, 2025 08:35

Refactor next_start_date, add best_run_id

11c5703

Revert some changes meant for another PR

93947ce

Revcert changes to next_start_date (will be done in subsequent PR)

8870072

Refactor start date

5029178

more tweaks

b7a37a6

feedback

dc016f0

mbertrand force-pushed the mb/next_start_date_2 branch from 75462fb to dc016f0 Compare November 20, 2025 13:36

mbertrand added Needs Review An open Pull Request that is ready for review and removed Waiting on author labels Nov 21, 2025

ChristopherChudzicki approved these changes Nov 22, 2025

View reviewed changes

Use best_run_id to determine start date on frontend; bring back next_run/date #2702

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mbertrand commented Nov 14, 2025 •

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