API 参考

use neon::prelude::*;

fn greet(mut cx: FunctionContext) -> JsResult {
    Ok(cx.string("Hello!"))
}

#[neon::main]
fn main(mut cx: ModuleContext) -> NeonResult<()> {
    cx.export_function("greet", greet)?;
    Ok(())
}

// 更简洁的方式
#[neon::export]
fn add(a: i32, b: i32) -> i32 {
    a + b
}

#[neon::export]
fn greet(name: String) -> String {
    format!("Hello, {}!", name)
}

fn example(mut cx: FunctionContext) -> JsResult {
    // 按索引获取参数
    let first: Handle = cx.argument(0)?;
    let second: Handle = cx.argument(1)?;
    
    // 获取并转换
    let num = cx.argument::(0)?.value(&mut cx);
    let text = cx.argument::(1)?.value(&mut cx);
    
    // 可选参数
    let optional = cx.argument_opt(2);
    if let Some(val) = optional {
        let s: Handle = val.downcast_or_throw(&mut cx)?;
    }
    
    Ok(cx.undefined())
}

// 返回字符串
fn get_string(mut cx: FunctionContext) -> JsResult {
    Ok(cx.string("Hello"))
}

// 返回数字
fn get_number(mut cx: FunctionContext) -> JsResult {
    Ok(cx.number(42.0))
}

// 返回对象
fn get_object(mut cx: FunctionContext) -> JsResult {
    let obj = cx.empty_object();
    let name = cx.string("Neon");
    obj.set(&mut cx, "name", name)?;
    Ok(obj)
}

// 返回数组
fn get_array(mut cx: FunctionContext) -> JsResult {
    let arr = cx.empty_array();
    let val = cx.number(1.0);
    arr.set(&mut cx, 0, val)?;
    Ok(arr)
}

fn may_fail(mut cx: FunctionContext) -> JsResult {
    let input = cx.argument::(0)?.value(&mut cx);
    
    if input.is_empty() {
        // 抛出 JavaScript 错误
        return cx.throw_error("Input cannot be empty");
    }
    
    Ok(cx.string(format!("Got: {}", input)))
}