### Access `VersionData` Runtime Information

Source: https://context7.com/jplatte/caniuse.rs/llms.txt

Shows how to retrieve and use `VersionData` at runtime, including filtering by version number and constructing URLs. Requires importing `VERSIONS`.

```rust
use crate::data::VERSIONS;

// Find version 1.31
let version = VERSIONS.iter().find(|v| v.number == "1.31");

if let Some(v) = version {
    println!("Release date: {:?}", v.release_date); // Some("2018-12-06")
    println!("Blog: {:?}", v.blog_post_path);
    // -> Some("2018/12/06/Rust-1.31-and-rust-2018/")

    // Build full URLs:
    if let Some(path) = v.blog_post_path {
        println!("https://blog.rust-lang.org/{path}");
    }
    if let Some(id) = v.gh_milestone_id {
        println!("https://github.com/rust-lang/rust/milestone/{id}");
    }
}

// Get all features that belong to 1.31
use crate::data::FEATURES;
let features_1_31: Vec<_> = FEATURES.iter()
    .filter(|f| matches!(f.version, Some(v) if v.number == "1.31"))
    .collect();
```

--------------------------------

### Initialize WASM Application

Source: https://context7.com/jplatte/caniuse.rs/llms.txt

This JavaScript code initializes the WebAssembly module and runs the Yew application. It handles theme restoration, checks for WebAssembly support, and then mounts the Yew app into the main DOM element.

```javascript
// src/main.js — bundled by rollup into public/caniuse_rs.js

import init, { run } from '../pkg/caniuse_rs.js';

// Restore or detect preferred color theme
let theme;
try { theme = localStorage.getItem("theme"); } catch (_e) {}
if (typeof theme !== "string") {
    theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "dark" : "light";
}
document.documentElement.dataset.theme = theme;  // sets data-theme="dark"|"light"

// Load and start the WASM app (only if WebAssembly is supported)
if ('WebAssembly' in window) {
    async function main() {
        await init('/caniuse_rs.wasm');  // fetch + instantiate the WASM module
        run();                           // mount the Yew app into <main>
    }
    main();
}

```

--------------------------------

### Mount Yew App in WASM

Source: https://context7.com/jplatte/caniuse.rs/llms.txt

This Rust snippet is the WASM entry point. It selects the main DOM element and renders the root Yew component into it.

```rust
// src/lib.rs
#[wasm_bindgen]
pub fn run() {
    let page = document().query_selector("main").unwrap().unwrap();
    yew::Renderer::<components::App>::with_root(page).render();
}

```

--------------------------------

### Generate Static Data Arrays (`build.rs`)

Source: https://context7.com/jplatte/caniuse.rs/llms.txt

Illustrates the static arrays generated by the build script for use at compile time. These include version data, feature data, and ngram search indices.

```rust
pub static VERSIONS: &[VersionData] = &[
    VersionData {
        number: "1.79",
        channel: Channel::Stable,
        release_date: Some("2024-06-13"),
        release_notes: None,
        blog_post_path: Some("2024/06/13/Rust-1.79.0/"),
        gh_milestone_id: Some(118),
    },
    // ... all versions sorted newest-first ...
];

pub static FEATURES: &[FeatureData] = &[
    FeatureData {
        title: "`io::Cursor::new` as `const fn`",
        flag: Some("const_io_structs"),
        slug: "const_io_cursor_new",
        version: Some(&VERSIONS[0]),
        impl_pr_id: Some(78811),
        tracking_issue_id: Some(78812),
        stabilization_pr_id: Some(124049),
        doc_path: Some("std/io/struct.Cursor.html#method.new"),
        items: &["std::io::Cursor::new"],
        // ... other optional fields as None ...
    },
    // ...
];

// Ngram search indices — built at compile time:
pub static FEATURE_MONOGRAM_INDEX: once_cell::sync::Lazy<HashMap<u8, &[u16]>> = ...;
pub static FEATURE_BIGRAM_INDEX:   once_cell::sync::Lazy<HashMap<[u8; 2], &[u16]>> = ...;
pub static FEATURE_TRIGRAM_INDEX:  once_cell::sync::Lazy<HashMap<[u8; 3], &[u16]>> = ...;
```

--------------------------------

### Development CLI Commands

Source: https://context7.com/jplatte/caniuse.rs/llms.txt

These bash commands utilize the `cargo xtask` helper for common development tasks such as building the site in development or release mode, serving it locally, and deploying it.

```bash
# Build the site in development mode (fast, no optimizations)
cargo xtask build --dev

# Build in release mode (wasm-opt size optimizations via wasm-pack)
cargo xtask build

# Build and serve locally at http://localhost:8000 (development mode by default)
cargo xtask serve

# Build (release) and serve locally
cargo xtask serve --release

# Build (release) and deploy to caniuse.rs via rsync + ssh
cargo xtask deploy

```

--------------------------------

### Access `FeatureData` Runtime Information

Source: https://context7.com/jplatte/caniuse.rs/llms.txt

Demonstrates how to access and filter `FeatureData` at runtime using static arrays. Requires importing `FEATURES` and `Channel`.

```rust
use crate::data::{FEATURES, Channel};

// Find a feature by slug
let feature = FEATURES.iter().find(|f| f.slug == "conservative_impl_trait");

if let Some(f) = feature {
    println!("Title: {}", f.title);                         // "`impl Trait` in function return types"
    println!("Flag: {:?}", f.flag);                         // Some("conservative_impl_trait")
    println!("Version: {:?}", f.version.map(|v| v.number)); // Some("1.26")
    println!("Stable: {}", f.is_on_channel(Channel::Stable)); // true
    println!("Tracking issue: {:?}", f.tracking_issue_id); // Some(34511)
}

// Check all stable features
let stable: Vec<_> = FEATURES.iter()
    .filter(|f| f.is_on_channel(Channel::Stable))
    .collect();

// Check unstable (nightly-only) features — version is None
let unstable: Vec<_> = FEATURES.iter()
    .filter(|f| f.version.is_none())
    .collect();
```

--------------------------------

### TOML Metadata for Rust Versions

Source: https://context7.com/jplatte/caniuse.rs/llms.txt

Stores metadata for Rust versions, including release date, blog post path, and GitHub milestone ID. Each TOML file in `data/` must have a corresponding entry here.

```toml
# data/versions.toml
["1.79"]
release_date = "2024-06-13"
gh_milestone_id = 118
blog_post_path = "2024/06/13/Rust-1.79.0/"

["1.31"]
release_date = "2018-12-06"
release_notes = "version-1310-2018-12-06"
gh_milestone_id = 58
blog_post_path = "2018/12/06/Rust-1.31-and-rust-2018/"

```

--------------------------------

### Execute Ngram-Weighted Search

Source: https://context7.com/jplatte/caniuse.rs/llms.txt

This snippet demonstrates how to perform a search using pre-allocated score buffers for efficiency. It extracts search terms and then runs the search, printing the results. The score buffer can be reused for subsequent searches.

```rust
use crate::search::{extract_search_terms, run_search};
use crate::data::FEATURES;

// Allocate a reusable score buffer (one entry per feature)
let mut search_scores = vec![(0u16, 0.0f64); FEATURES.len()];

// Run a search
let terms = extract_search_terms("impl trait").unwrap();
let results = run_search(&terms, &mut search_scores);

for feature in &results {
    let version_str = feature.version.map(|v| v.number).unwrap_or("unstable");
    println!("{} (since {})", feature.title, version_str);
}
// Example output:
// `impl Trait` in function return types (since 1.26)
// `impl Trait` in function arguments (since 1.26)
// ...

// The score buffer can be reused across searches for efficiency
let terms2 = extract_search_terms("async").unwrap();
let results2 = run_search(&terms2, &mut search_scores);
```

--------------------------------

### Static JSON API for Rust Features

Source: https://context7.com/jplatte/caniuse.rs/llms.txt

This JSON file is generated at build time and provides the complete feature dataset for external tooling. It is served at https://caniuse.rs/features.json.

```json
{
  "versions": {
    "1.79": {
      "channel": "stable",
      "release_date": "2024-06-13",
      "gh_milestone_id": 118,
      "blog_post_path": "2024/06/13/Rust-1.79.0/"
    }
  },
  "features": {
    "const_io_cursor_new": {
      "title": "`io::Cursor::new` as `const fn`",
      "flag": "const_io_structs",
      "impl_pr_id": 78811,
      "tracking_issue_id": 78812,
      "stabilization_pr_id": 124049,
      "items": ["std::io::Cursor::new"],
      "doc_path": "std/io/struct.Cursor.html#method.new",
      "version": "1.79"
    },
    "conservative_impl_trait": {
      "title": "`impl Trait` in function return types",
      "flag": "conservative_impl_trait",
      "tracking_issue_id": 34511,
      "edition_guide_path": "rust-2018/trait-system/impl-trait-for-returning-complex-types-with-ease.html",
      "version": "1.26"
    }
  }
}
```

--------------------------------

### Define Client-Side Routes with Yew Router

Source: https://context7.com/jplatte/caniuse.rs/llms.txt

This enum defines the routes for the Yew application using `yew-router`. Each variant maps to a specific URL path and is associated with a corresponding component or view.

```rust

#[derive(Clone, Debug, PartialEq, Routable)]
enum AppRoute {
    #[at("/features/:name")]  // Feature detail page  → FeaturePage component
    Feature { name: String },

    #[at("/versions/:number")] // Version detail page → VersionPage component
    Version { number: String },

    #[at("/about")]            // About page          → About component
    About,

    #[at("/recent")]           // Recently stabilized → Index (RecentlyStabilized mode)
    RecentlyStabilized,

    #[at("/unstable")]         // Nightly features    → Index (Unstable mode)
    Unstable,

    #[at("/")]                 // Search homepage     → Index (Stable mode)
    Index,
}

// Example URLs:
// https://caniuse.rs/                          → Stable feature list + search
// https://caniuse.rs/features/conservative_impl_trait → Feature detail
// https://caniuse.rs/versions/1.31             → All features in Rust 1.31
// https://caniuse.rs/unstable                  → Nightly-only features
// https://caniuse.rs/recent                    → Beta/recently-stabilized features

```

--------------------------------

### Extract Search Terms (`src/search.rs`)

Source: https://context7.com/jplatte/caniuse.rs/llms.txt

Parses a query string into search terms, validating for backticks and non-ASCII characters. Returns an `Err(InvalidSearchQuery)` for invalid input.

```rust
use crate::search::{extract_search_terms, InvalidSearchQuery};

// Valid queries
assert_eq!(extract_search_terms("impl trait").unwrap(), vec!["impl", "trait"]);
assert_eq!(extract_search_terms("  async  await  ").unwrap(), vec!["async", "await"]);
assert_eq!(extract_search_terms("").unwrap(), Vec::<String>::new());

// Invalid query (backtick or non-ASCII)
assert!(extract_search_terms("`async`").is_err());
assert!(matches!(extract_search_terms("café"), Err(InvalidSearchQuery)));
```

--------------------------------

### TOML Definition for Rust Feature

Source: https://context7.com/jplatte/caniuse.rs/llms.txt

Defines a Rust feature with its title, flag, and tracking information. All fields except title are optional. The filename serves as the URL slug.

```toml
# data/1.26/conservative_impl_trait.toml
title = "`impl Trait` in function return types"
flag = "conservative_impl_trait"
tracking_issue_id = 34511
edition_guide_path = "rust-2018/trait-system/impl-trait-for-returning-complex-types-with-ease.html"

```

```toml
# data/1.79/const_io_cursor_new.toml
title = "`io::Cursor::new` as `const fn`"
flag = "const_io_structs"
impl_pr_id = 78811
tracking_issue_id = 78812
stabilization_pr_id = 124049
items = ["std::io::Cursor::new"]
doc_path = "std/io/struct.Cursor.html#method.new"

```

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