aex/MODERNIZE.md

# MODERNIZE.md

A list of dependency reductions and idiom cleanups for the current codebase.
Nothing here is applied yet. Review it, then decide which items to do and when
(most fit in ROADMAP Phase 0).

Status notes:
- Every "unused" claim below was verified with a grep: 0 references in `src/`.
- Toolchain decision: stay on nightly (channel = "nightly"). The stable-Rust
  item is listed for awareness only.
- The item 3.2 note about the double `foundry.json` load stays true.
- Dependency decision (2026-08-04): `itertools`, `thiserror`, `anyhow`,
  `pretty_env_logger`, `dotenvy` stay for certain. The rest of section 1
  is under consideration.

## 1. Unused dependencies

None of these are referenced in `src/`. Decision: `itertools`, `thiserror`,
`anyhow`, `pretty_env_logger` and `dotenvy` stay for certain. The rest is
under consideration.

| dependency | note |
|---|---|
| `itertools` | **keep for now** (decision). No usage |
| `seq-macro` | under consideration. No usage |
| `leptos-use` | under consideration. No usage |
| `dotenvy` | **keep for now** (decision). No usage. Never wired into `main` |
| `pretty_env_logger` | **keep for now** (decision). No usage. Logging uses the `log` macros |
| `thiserror` | **keep for now** (decision). No usage. No error types yet |
| `http` | under consideration. Optional, enabled by no feature. Code uses `actix_web::http::StatusCode` |
| `console_log` | under consideration. No usage. Only `console_error_panic_hook` is called |
| `anyhow` | **keep for now** (decision). Only `#[macro_use] extern crate anyhow` and prelude aliases. The `Result` alias and `bail!`/`anyhow!` are used nowhere |
| `js-sys` | under consideration. No direct usage. Resolves transitively. Keep the `wasm-bindgen =0.2.126` pin: `hydrate()` uses `#[wasm_bindgen(...)]` |

## 2. Replace crates with std or small local code

1. **`lazy_static` → `std::sync::LazyLock`** (stable since 1.80).
   Rewrite `src/statics/mod.rs`:

   ```rust
   use std::sync::LazyLock;

   static ITEMS_REFS: LazyLock<ItemReferenceMap> = LazyLock::new(|| {
       let mut map = HashMap::with_capacity(5_000);
       utils::read_items(include_str!("../../data/items.json"), &mut map);
       // base.json, foundry.json (twice — duplication bug), magic.json
       info!("Loaded {} items", map.len());
       ItemReferenceMap(map)
   });

   static ITEMS_NAMES: LazyLock<Vec<&'static str>> =
       LazyLock::new(|| ITEMS_REFS.0.keys().map(String::as_str).collect());
   ```

   Notes:
   - `include_str!` needs literal paths, so keep the five explicit calls.
   - The current `HashMap::from_iter(map.into_iter())` roundtrip is a no-op.
     Wrap the map directly.
   - `ITEMS_NAMES` changes from `Vec<&'static String>` to `Vec<&'static str>`.
     The matcher accepts both.

2. **`num-format` → local `group_thousands` helper** in `src/utils/mod.rs`.
   It exists only for the `ToFormattedString` bound in `Numput`. Drop the
   bound and render `f.to_string()` grouped. About 6 lines.

3. **`num-traits` → local saturating trait** in `src/components/numput.rs`.
   It exists only for the `SaturatingAdd`/`SaturatingSub` bounds on `Numput`.
   Define a small local trait and impl it for `u8`, `u16`, `u32`, `u64`,
   `usize`. `Numput` keeps its generics.

4. **`serde` (direct) → remove now, re-add in ROADMAP phase 1.**
   No derives exist today; `serde_json::Value` works without naming `serde`
   in `Cargo.toml`. Phase 1 (persistence) re-adds
   `serde = { version = "1", features = ["derive"] }`.

Result: dropping the under-consideration items takes `[dependencies]` from
27 entries to about 18. If the five kept deps are dropped later too, it goes
to about 13.

## 3. Idiomatic cleanups (no dependency changes)

1. Delete `#![feature(type_alias_impl_trait)]` in `src/lib.rs:6`.
   It is unused and warns.

2. Stay on nightly. The code uses only stable features (let-chains, let-else,
   edition 2024, `LazyLock`). If the toolchain is ever revisited: drop the
   `nightly` features from `leptos`/`leptos_router`, install stable, and run
   the three checks. The original build breakage was a nightly regression
   (`min_adt_const_params` re-gating in nightly 1.99); stable does not have
   that class of failure.

3. Prelude (`src/prelude.rs`):
   - Remove the blanket `#![allow(unused_imports)]` and
     `#![allow(dead_code)]`. They hide real warnings.
   - Remove the single-letter `log` aliases
     (`warn as w, log as l, info as i, ...`). They are unused.
   - Remove the `anyhow` re-exports and typealiases. Keeping the `anyhow`
     dependency does not force keeping these dead re-exports.
   - Replace legacy `#[macro_use] extern crate log;` in `src/lib.rs` with
     `use log::{info, error};` at the two call sites.

4. `read_items` (`src/utils/mod.rs`): use the `Entry` API instead of
   `contains_key` → `get_mut().unwrap()`. Removes the unwrap and the double
   lookup.

5. Mock data (`src/entities/mock.rs`):
   `HashSet::from_iter(vec![...])` → `HashSet::from([...])`.
   The date `unwrap`s are fine: the data is static.

6. Minor: `adjust_checked` drops `-> ()`; `numput.rs` drops the unused
   `leptos::{ logging, ... }` import.

## 4. Opinionated (do only on request)

1. `chrono` → `jiff`. Nicer API, actively maintained. Not worth the churn
   for this model. If kept: `chrono`'s `serde` feature is unused today —
   trim it now, re-add in phase 1.
2. `cargo fmt` normalization. The repo uses `fn foo (` spacing; it may be
   deliberate. Ask before running.
3. Clippy pass over the result.

## Verification

After applying items 1-3, run:

```
cargo check --no-default-features --features hydrate --lib
cargo check --no-default-features --features ssr --bin aex
cargo check --target wasm32-unknown-unknown --no-default-features --features hydrate --lib
```