2022

class相关

  1. class X {
  2.   #a; // 私有变量
  3.   #b=1
  4.   get b() { //get、set
  5.     return this.#b;
  6.   }
  7.   static getBofX(x) {
  8.     if(#b in x) return x.#b
  9.     else return 'fail'
  10.   }
  11.   static { //静态块
  12.     console.log('hello')
  13.   }
  14. }
  16. try {
  17. }catch(e) {
  18.   console.log(e);
  19. }

top-level await

  1. // users.js
  2. export const users = await fetch('/users/lists');
  4. // usage.js
  5. import { users } from "./users.js";
  6. // ✅ the module will wait for users to be fullfilled prior to executing any code
  7. console.log(users);

在web开发中，当同时使用事件监听和top-level await，会导致代码的执行顺序不确定。

Error cause

  1. async function f(url) {
  2.   try {
  3.     let x = await fetch(url);
  4.   } catch(e) {
  5.     throw new Error("fail", {cause: e})
  6.   }
  7. }
  9. try {
  10.   await f("x:x");
  11. } catch (e) {
  12.   console.log(e, e.cause);
  13. }

参考

【1】https://www.ecma-international.org/
【2】https://yanhaijing.com/es5/#about