From 96eec9ce110875499351ee08f86f586875748a0b Mon Sep 17 00:00:00 2001
From: Ken Hibino <ken.hibino7@gmail.com>
Date: Fri, 4 Dec 2020 06:48:58 -0800
Subject: [PATCH] Fix no previous enqueue entry's UI display

---
 conversion_helpers.go                       | 13 +++++---
 ui/src/api.ts                               |  4 ++-
 ui/src/components/SchedulerEntriesTable.tsx | 36 ++++++++++++---------
 3 files changed, 32 insertions(+), 21 deletions(-)

diff --git a/conversion_helpers.go b/conversion_helpers.go
index 2f49e93..93381f5 100644
--- a/conversion_helpers.go
+++ b/conversion_helpers.go
@@ -219,8 +219,9 @@ type SchedulerEntry struct {
 	TaskType      string        `json:"task_type"`
 	TaskPayload   asynq.Payload `json:"task_payload"`
 	Opts          []string      `json:"options"`
-	NextEnqueueAt time.Time     `json:"next_enqueue_at"`
-	PrevEnqueueAt time.Time     `json:"prev_enqueue_at"`
+	NextEnqueueAt string        `json:"next_enqueue_at"`
+	// This field is omitted if there were no previous enqueue events.
+	PrevEnqueueAt string `json:"prev_enqueue_at,omitempty"`
 }
 
 func toSchedulerEntry(e *asynq.SchedulerEntry) *SchedulerEntry {
@@ -228,14 +229,18 @@ func toSchedulerEntry(e *asynq.SchedulerEntry) *SchedulerEntry {
 	for _, o := range e.Opts {
 		opts = append(opts, o.String())
 	}
+	prev := ""
+	if !e.Prev.IsZero() {
+		prev = e.Prev.Format(time.RFC3339)
+	}
 	return &SchedulerEntry{
 		ID:            e.ID,
 		Spec:          e.Spec,
 		TaskType:      e.Task.Type,
 		TaskPayload:   e.Task.Payload,
 		Opts:          opts,
-		NextEnqueueAt: e.Next,
-		PrevEnqueueAt: e.Prev,
+		NextEnqueueAt: e.Next.Format(time.RFC3339),
+		PrevEnqueueAt: prev,
 	}
 }
 
diff --git a/ui/src/api.ts b/ui/src/api.ts
index a7a2c75..19d40a1 100644
--- a/ui/src/api.ts
+++ b/ui/src/api.ts
@@ -108,7 +108,9 @@ export interface SchedulerEntry {
   task_payload: { [key: string]: any };
   options: string[];
   next_enqueue_at: string;
-  prev_enqueue_at: string;
+  // prev_enqueue_at will be omitted
+  // if there were no previous enqueue events.
+  prev_enqueue_at?: string;
 }
 
 export interface PaginationOptions extends Record<string, number | undefined> {
diff --git a/ui/src/components/SchedulerEntriesTable.tsx b/ui/src/components/SchedulerEntriesTable.tsx
index a216d6d..d669ee5 100644
--- a/ui/src/components/SchedulerEntriesTable.tsx
+++ b/ui/src/components/SchedulerEntriesTable.tsx
@@ -118,36 +118,38 @@ export default function SchedulerEntriesTable(props: Props) {
     }
   };
 
-  const cmpFunc = (e1: SchedulerEntry, q2: SchedulerEntry): number => {
+  const cmpFunc = (e1: SchedulerEntry, e2: SchedulerEntry): number => {
     let isE1Smaller: boolean;
     switch (sortBy) {
       case SortBy.EntryId:
-        if (e1.id === q2.id) return 0;
-        isE1Smaller = e1.id < q2.id;
+        if (e1.id === e2.id) return 0;
+        isE1Smaller = e1.id < e2.id;
         break;
       case SortBy.Spec:
-        if (e1.spec === q2.spec) return 0;
-        isE1Smaller = e1.spec < q2.spec;
+        if (e1.spec === e2.spec) return 0;
+        isE1Smaller = e1.spec < e2.spec;
         break;
       case SortBy.Type:
-        if (e1.task_type === q2.task_type) return 0;
-        isE1Smaller = e1.task_type < q2.task_type;
+        if (e1.task_type === e2.task_type) return 0;
+        isE1Smaller = e1.task_type < e2.task_type;
         break;
       case SortBy.Payload:
-        if (e1.task_payload === q2.task_payload) return 0;
-        isE1Smaller = e1.task_payload < q2.task_payload;
+        if (e1.task_payload === e2.task_payload) return 0;
+        isE1Smaller = e1.task_payload < e2.task_payload;
         break;
       case SortBy.Options:
-        if (e1.options === q2.options) return 0;
-        isE1Smaller = e1.options < q2.options;
+        if (e1.options === e2.options) return 0;
+        isE1Smaller = e1.options < e2.options;
         break;
       case SortBy.NextEnqueue:
-        if (e1.next_enqueue_at === q2.next_enqueue_at) return 0;
-        isE1Smaller = e1.next_enqueue_at < q2.next_enqueue_at;
+        if (e1.next_enqueue_at === e2.next_enqueue_at) return 0;
+        isE1Smaller = e1.next_enqueue_at < e2.next_enqueue_at;
         break;
       case SortBy.PrevEnqueue:
-        if (e1.prev_enqueue_at === q2.prev_enqueue_at) return 0;
-        isE1Smaller = e1.prev_enqueue_at < q2.prev_enqueue_at;
+        const e1PrevEnqueueAt = e1.prev_enqueue_at || "";
+        const e2PrevEnqueueAt = e2.prev_enqueue_at || "";
+        if (e1PrevEnqueueAt === e2PrevEnqueueAt) return 0;
+        isE1Smaller = e1PrevEnqueueAt < e2PrevEnqueueAt;
         break;
       default:
         // eslint-disable-next-line no-throw-literal
@@ -228,7 +230,9 @@ export default function SchedulerEntriesTable(props: Props) {
                   {durationBefore(entry.next_enqueue_at)}
                 </TableCell>
                 <TableCell className={clsx(isLastRow && classes.noBorder)}>
-                  {timeAgo(entry.prev_enqueue_at)}
+                  {entry.prev_enqueue_at
+                    ? timeAgo(entry.prev_enqueue_at)
+                    : "N/A"}
                 </TableCell>
               </TableRow>
             );