Elixir Essentials

RULES — Follow these with no exceptions

1. Use pattern matching over if/else for control flow and data extraction
2. Add @impl true before every callback function (mount, handle_event, handle_info, etc.)
3. Return {:ok, result} | {:error, reason} tuples for fallible operations
4. Use with for 2+ sequential fallible operations instead of nested case
5. Use the pipe operator for 2+ chained transformations
6. Never nest if/else statements — use case, cond, or multi-clause functions
7. Predicate functions end with ?, dangerous functions end with !
8. Let it crash — don't write defensive code for impossible states

Pattern Matching

Pattern matching is the primary control flow mechanism in Elixir. Prefer it over conditional statements.