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_tl;dr - anyone know why `maybeSingle()` errors wh...
# help
x
tl;dr - anyone know why 
maybeSingle()
errors when 0 rows are returned? I thought that was the whole point of it over 
.single()
 I've got a many:many join table called `teams_users`:
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ts
id // auto-increment
created_at // NOW()
team_id // foreign key teams.id
user_id // foreign key users.id
When I do the following:
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ts
supabase
  .from("teams_users")
  .select("id")
  .match({ team_id, user_id })
  .maybeSingle();
I get an 
406 Not Acceptable
error:
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json
{
  "message":"JSON object requested, multiple (or no) rows returned",
  "details":"Results contain 0 rows, application/vnd.pgrst.object+json requires 1 row"
}
The docs are pretty barebones atm so difficult to learn from but includes this quote: > Result must be at most one row (e.g. using eq on a UNIQUE column), otherwise this will result in an error. The 
e.g. using eq on a UNIQUE column
strikes me as just an example, can 
maybeSingle()
ONLY be used after passing a primary key in to 
.match/.eq
?
n
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x
It's not the biggest problem, I've sidestepped it by doing
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ts
const { data, error } = await supabase
  .from("teams_users")
  .select("id")
  .match({ team_id, user_id });

if ((data || []).length > 0) doTheThings();
as opposed to the neater and preferred:
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ts
const { data, error } = await supabase
  .from("teams_users")
  .select("id")
  .match({ team_id, user_id })
  .maybeSingle();

if (data) doTheThings();
But I am curious as to why it doesn't work as expected.
g
So are you actually getting an error back from the await? The network response will have 406, but the postgrest.js code checks for the error and returns correct data with error = null for the case of 0 rows.
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maybeSingle(): PromiseLike<PostgrestMaybeSingleResponse<T>> {
    this.headers['Accept'] = 'application/vnd.pgrst.object+json'
    const _this = new PostgrestTransformBuilder(this)
    _this.then = ((onfulfilled: any, onrejected: any) =>
      this.then((res: any): any => {
        if (res.error?.details?.includes('Results contain 0 rows')) {
          return onfulfilled({
            error: null,
            data: null,
            count: res.count,
            status: 200,
            statusText: 'OK',
            body: null,
          })
        }

        return onfulfilled(res)
      }, onrejected)) as any
    return _this as PromiseLike<PostgrestMaybeSingleResponse<T>>
  }
n
xephyr (2022-05-08)
x
Looks like that's exactly what I get yeah, do we know why it is returning 406 when the status 200/OK though?
g
It is supabase.js (actually postgres.js) hiding the error from single() to PostgREST. There is really no method to do maybeSingle() there, so they just know they can ignore that specific error and return in data/error what you would expect.
x
Ah oaky, so if I want clean console/network tab I should 
.limit(1)
or omit the modifier entirely and just handle it as I did above? (
.length > 0
etc)
g
limit 1 would return an array of 1 item or empty array, so as long as you can deal with that yes.
Oh except it won't error if there were 2 results on the server....
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