WebAssembly 实战：使用 Rust 开发高性能 Web 应用

# 安装 Rust
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

# 添加 WASM 目标
rustup target add wasm32-unknown-unknown

# 安装 wasm-pack
cargo install wasm-pack

cargo new --lib wasm-demo
cd wasm-demo

use wasm_bindgen::prelude::*;

/// 计算斐波那契数列（递归版本）
#[wasm_bindgen]
pub fn fibonacci(n: u32) -> u64 {
    match n {
        0 => 0,
        1 => 1,
        _ => fibonacci(n - 1) + fibonacci(n - 2),
    }
}

/// 计算阶乘
#[wasm_bindgen]
pub fn factorial(n: u32) -> u64 {
    (1..=n as u64).product()
}

/// 冒泡排序（对 i32 数组排序）
#[wasm_bindgen]
pub fn bubble_sort(arr: &mut [i32]) {
    let len = arr.len();
    for i in 0..len {
        for j in 0..len - i - 1 {
            if arr[j] > arr[j + 1] {
                arr.swap(j, j + 1);
            }
        }
    }
}

[package]
name = "wasm-demo"
version = "0.1.0"
edition = "2021"

[lib]
crate-type = ["cdylib"]

[dependencies]
wasm-bindgen = "0.2"

wasm-pack build --target web

import init, { fibonacci, factorial, bubble_sort } from './pkg/wasm_demo.js';

async function run() {
    await init();
    
    // 测试斐波那契
    console.log('Fibonacci(40):', fibonacci(40)); // 比 JS 快 10 倍+
    
    // 测试阶乘
    console.log('Factorial(20):', factorial(20));
    
    // 测试排序
    let arr = [64, 34, 25, 12, 22, 11, 90];
    bubble_sort(arr);
    console.log('Sorted:', arr); // [11, 12, 22, 25, 34, 64, 90]
}

run();