ElixirDrops

Use `Ecto.Multi` for complex transactions in Phoenix contexts

Manual transaction management with nested operations becomes unreadable and error-prone. Ecto.Multi provides named operations, automatic rollback, and...

almirsarajcic

yesterday

0

Live Sessions in Phoenix LiveView: Reducing navigation time between LiveViews

The main idea behind live sessions is to reduce navigation time when navigating a group of routes. Normally what happens when navigating between LiveV...

Deankinyua

2 days ago

0

`File.stream!/1` processes large files with constant memory

File.read!/1 loads the entire file into memory. A 2GB log file? That's 2GB of RAM. Use File.stream!/1 to process files line-by-line with constant memo...

almirsarajcic

8 days ago

2

Stop using `Repo.preload` in loops - use `preload` in queries

Calling Repo.preload/2 inside Enum.map or comprehensions creates N+1 queries - one query to fetch the parent records, then one additional query for ea...

almirsarajcic

15 days ago

0

Use `Task.Supervisor` instead of bare `Task.async`

Bare Task.async creates linked tasks that can crash your process or leave zombie tasks running. Task.Supervisor provides supervised tasks with automat...

almirsarajcic

22 days ago

0

Prevent race conditions with `Ecto.Query.lock/2`

Two users buying the last item simultaneously can cause overselling. Use PostgreSQL row locks with lock: "FOR UPDATE" to prevent concurrent updates fr...

almirsarajcic

29 days ago

0

Use `temporary_assigns` for large lists in LiveView

Sending entire lists over the socket on every LiveView update kills performance. Mark list assigns as temporary to send them once and drop them from s...

almirsarajcic

1 month ago

0

Use `send_update_after/4` for delayed LiveComponent updates

Manual timer management with Process.send_after/3 in LiveComponents creates cleanup complexity. LiveView's send_update_after/4 handles delayed updates...

almirsarajcic

1 month ago

0

Use router `on_mount` hooks instead of duplicating LiveView mount logic

Copy-pasting the same assigns across every LiveView mount/3 function creates maintenance nightmares. Router-level on_mount hooks run automatically bef...

almirsarajcic

1 month ago

0

Stop mixing LiveView handlers with JavaScript hooks

Handling the same event in both Phoenix and JavaScript creates race conditions and unpredictable behavior. Keep server logic in LiveView handlers and ...

almirsarajcic

1 month ago

0

The amazing v/1 helper function

I may be late on this one but today I learned about the v/1, a helper function that retrieves the value from a previous expression by its line number ...

jrowah

2 months ago

0

Phoenix contexts should return tuples, not raise

Phoenix context functions that raise exceptions break LiveView error handling and force try/catch everywhere. Tagged tuples enable composable error ha...

almirsarajcic

2 months ago

0

Prevent duplicate Oban jobs with `unique` worker options

Multiple button clicks or retries can enqueue the same background job multiple times, causing duplicate charges, emails, or API calls. Oban's built-in...

almirsarajcic

2 months ago

0

Stop rewriting Ecto queries from scratch - use `Ecto.Query.exclude/2` instead

Building complex queries often means starting with a base query, then customizing it for different use cases. Most developers duplicate the entire que...

almirsarajcic

2 months ago

0

Fixing `Ecto.StaleEntryError` with optimistic locking patterns

Race conditions in concurrent updates cause cryptic Ecto.StaleEntryError crashes in production. The error happens when multiple processes try to updat...

almirsarajcic

2 months ago

0