注入 This

在类方法中，您可能希望访问 Class 实例的原始 Object 值。

lib.rs

rust

use napi::{bindgen_prelude::*, JsObject};
use napi_derive::napi;

#[napi]
pub struct QueryEngine {}

#[napi]
impl QueryEngine {
  #[napi(constructor)]
  pub fn new() -> Result<Self> {
    Ok(Self {})
  }

  #[napi]
  pub fn get_ref_count(&self, this: This<JsObject>) -> Result<Option<i32>> { 
    this.get::<i32>("refCount")
  }
}

main.mjs

import { QueryEngine } from './index.js'

const qe = new QueryEngine()
qe.refCount = 3
console.log(qe.getRefCount()) // 3

在函数中，它可能会绑定到 JavaScript 中的某些对象：

lib.rs

rust

use napi::bindgen_prelude::*;
use napi_derive::napi;

#[napi(constructor)]
pub struct Width {
  pub value: i32,
}

#[napi]
pub fn plus_one(this: This<&Width>) -> i32 { 
  this.value + 1
}

main.mjs

import { Width, plusOne } from './index.js'

const width = new Width(1)
console.log(plusOne.call(width)) // 2

# 注入 This

注入 This