justjavac

// 需要通过 node --allow-natives-syntax 参数运行
const { GCSignal, consumeSignals, trackGarbageCollection } = require("gc-signals");

function fn() {
    // 创建两个局部变量
    const a1 = new GCSignal(1);
    const a2 = new GCSignal(2);
    global.tmp = a2;  // 将 a2 变量赋值给全局变量
    const o = {};
    trackGarbageCollection(o, 3); // 跟踪局部变量 o 的 GC 状态，标识为 3

justjavac

在 npm 5.1 或者更低版本中，不存在 npx 命令。因此，你必须全局安装 create-next-app：

npm install -g create-next-app

然后再运行：

create-next-app

justjavac

%GetOptimizationStatus return a set of bitwise flags instead of a single value, to access the value, you need to take the binary representation of the returned value. Now, for example, if 65 is returned, the binary representation is the following:

(65).toString(2).padStart(12, '0');
// 000001000001

Each binary digit acts as a boolean with the following meaning:

justjavac

// JavaScript 字符串编码使用 UTF-16
"💩".length === 2;
"💩" === "\u{1F4A9}";    // es6
"💩" === "\uD83D\uDCA9"; // es5

// 同一个编码可能使用不同的码位
"ò" === "ò";       // ❎
"ò" === "\xF2";    // ✅
"ò" === "o\u0300"; // ✅
"o\u0300".normalize("NFC") === "\xF2"; // ✅ es6 提供了 normalize 函数

justjavac

function wtf() {  
  ( [ {} ] )
  [ ( {} ) ]
  { ( [] ) }
}

justjavac

PDF完整版：https://github.com/huangjunsen/GooFlow/files/2078684/_.Issue.12.sdlddr_Gooflow.pdf

justjavac

{"sig":"32a34af259b837df4e02abb1a71bfefe6de6637a393fd3b6194a3578ede5fcb28306c9e1da1ba29ee71c3450331e960a946823525cef5eb8a8ada9a32de65f080","msghash":"f2f38ac068f4440b69248eea0bf2d8be85aa6eb9f233ca92239e28d721cbe188"}

justjavac

let reslt, x;

reslt = [...null]; // TypeError: null is not iterable
reslt = [...undefined]; // TypeError: undefined is not iterable

reslt = {...null}; // {}
reslt = {...undefined}; // {}

if (x in null) {}
// TypeError: Cannot use 'in' operator to search for 'undefined' in null

justjavac

function test() {
  const a = new Int32Array(10);
  for (let i = 0; i < 1e6; i++) {
    a.set([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
  }
  return a;
}

console.time('test');
test();

justjavac

// https://github.com/chaosbot/Chaos/blob/master/server/static/js/chaos.js
var canvas = document.createElement("canvas");
document.getElementsByClassName("content")[0].appendChild(canvas);
var ctx = canvas.getContext("2d");

canvas.width = 400;
canvas.height = 200;

ctx.fillStyle = "#000000";
ctx.fillRect(0, 0, canvas.width, canvas.height);