Analyze LiveView socket assigns for memory efficiency, clarity, and best practices.
\nUse Grep to find all assign( and assign_new( calls in the target LiveView file.
Use Grep to find large data patterns: lists stored in assigns (assign.*\\[\\], assign.*Repo\\.all) and full schema storage (assign.*Repo\\.get) in the target file.
| Pattern | \nProblem | \nSolution | \n
|---|---|---|
assign(:items, Repo.all(...)) | \nUnbounded list | \nUse stream/3 | \n
assign(:user, Repo.get!(...)) | \nFull schema | \nSelect only needed fields | \n
assign(:file_data, binary) | \nLarge binary | \nStore reference, not data | \n
| Nested preloads | \nExcessive data | \nPreload only what's rendered | \n
Should use temporary_assigns:
def mount(_params, _session, socket) do\n {:ok, socket, temporary_assigns: [flash_message: nil]}\nend\nSearch for assigns defined but never used in templates:
\nUse Grep to extract all assign names (assign\\(:(\\w+)) from the LiveView file, then use Grep to find all @\\w+ references in the corresponding .heex template. Compare to find unused assigns.
# BAD: @items might not exist\ndef render(assigns) do\n ~H\"<%= for item <- @items do %>\"\nend\n\n# GOOD: Initialize in mount\ndef mount(_params, _session, socket) do\n {:ok, assign(socket, items: [])}\nend\nFor each assign, estimate memory footprint:
\n| Data Type | \nApprox Size | \nConcern Level | \n
|---|---|---|
| Integer | \n8 bytes | \nLow | \n
| String (100 chars) | \n~200 bytes | \nLow | \n
| List of 100 maps | \n~10-50 KB | \nMedium | \n
| List of 1000 items | \n~100-500 KB | \nHigh | \n
| Binary (image) | \nVaries | \nCritical | \n
| Full Ecto schema | \n~1-5 KB each | \nMedium | \n
Run lv-assigns path/to/live_view.ex to generate an assigns inventory with memory estimates and optimization recommendations.