readTasks.go

c, err := db.Collection(collName).Find(ctx, bson.D{})
if err != nil {
	return fmt.Errorf("readTasks: couldn't list all to-dos: %v", err)
}
defer c.Close(ctx)
tw := tabwriter.NewWriter(os.Stdout, 24, 2, 4, ' ', tabwriter.TabIndent)
_, _ = fmt.Fprintln(tw, "ID\tCreated At\tModified At\tTask\t")
for c.Next(ctx) {
	elem := &bson.D{}
	if err = c.Decode(elem); err != nil {
		return fmt.Errorf("readTasks: couldn't make to-do item ready for display: %v", err)
	}
	m := elem.Map()
	t := todo{
		ID:         m["_id"].(primitive.ObjectID).Hex(),
		CreatedAt:  dateTimeMillis(m["createdAt"].(primitive.DateTime)),
		ModifiedAt: dateTimeMillis(m["modifiedAt"].(primitive.DateTime)),
		Task:       m["task"].(string),
	}
	output := fmt.Sprintf("%s\t%s\t%s\t%s\t",
		t.ID,
		formatForDisplay(t.CreatedAt),
		formatForDisplay(t.ModifiedAt),
		t.Task,
	)
	_, _ = fmt.Fprintln(tw, output)
	if err = tw.Flush(); err != nil {
		return fmt.Errorf("readTasks: all data for the to-do couldn't be printed: %v", err)
	}
}
if err = c.Err(); err != nil {
	return fmt.Errorf("readTasks: all to-do items couldn't be listed: %v", err)
}