关于js函数后是否加；的问题---学习廖雪峰老师的node课时出现的问题

在学习廖老师的node-mysql-使用Sequelize时，按照老师的代码敲出来，运行的时候一直报错

sequelize deprecated String based operators are now deprecated. Please use Symbol based operators for better security, read more at http://docs.sequelizejs.com/manual/tutorial/querying.html#operators node_modules\sequelize\lib\sequelize.js:242:13
F:\杂\廖雪峰\node\mysql\hello-sequelize\app.js:64
(async () =>{
^

TypeError: (intermediate value)(...) is not a function
    at Object.<anonymous> (F:\杂\廖雪峰\node\mysql\hello-sequelize\app.js:64:1)
    at Module._compile (module.js:652:30)
    at Object.Module._extensions..js (module.js:663:10)
    at Module.load (module.js:565:32)
    at tryModuleLoad (module.js:505:12)
    at Function.Module._load (module.js:497:3)
    at Function.Module.runMain (module.js:693:10)
    at startup (bootstrap_node.js:188:16)
    at bootstrap_node.js:609:3

百度了很长时间，都没有解决，于是在廖老师的github上直接复制了他的代码，发现竟然可以运行。在此之前，已经比较过很多遍。在自己用肉眼无法比较出差异之后，用beyond compare比较了一下，发现只是存在是否加；的差异。

const Sequelize = require('sequelize');
const config = require('./config');

// 创建一个sequelize对象实例
var sequelize = new Sequelize(config.database, config.username, config.password,{
  host: config.host,
  dialect: 'mysql',
  pool: {
    max: 5,
    min: 0,
    idle: 30000
  }
});

// 定义模型Pet，告诉sequelize如何映射数据库表
// sequelize返回的对象是promise
var Pet = sequelize.define('pet', {
  // 传入名称写单数，对应默认的表名为复数
  id: {
    type: Sequelize.STRING(50),
    primaryKey: true
  },
  name: Sequelize.STRING(100),
  gender: Sequelize.BOOLEAN,
  birth: Sequelize.STRING(10),
  createdAt: Sequelize.BIGINT,
  updatedAt: Sequelize.BIGINT,
  version: Sequelize.BIGINT
}, {
  // 关闭sequelize自动添加timestamps的功能
  timestamps: false
});

console.log(Date.now());
var now =Date.now();

Pet.create({
  id: 'g-' + now,
  name: 'Gaffey',
  gender: false,
  birth: '2007-07-07',
  createdAt: now,
  updatedAt: now,
  version: 0
}).then(function (p) {
  console.log('created.' + JSON.stringify(p));
}).catch(function (err) {
  console.log('failed: ' + err);
});

(async ()=>{
var dog =  await Pet.create({
    id: 'd-' + now,
    name:'333',
    gender: false,
    birth: '2008-08-09',
    createdAt: now,
    updatedAt: now,
    version:0
  });
  console.log('created' + JSON.stringify(dog))
})();

(async () =>{
  var pets = await Pet.findAll({
    where: {
      name: 'Gaffey'
    }
  })
  console.log(`find ${pets.length} pets`)
  for (let p of pets) {
    console.log(JSON.stringify(p))
  }
})()

我之前在第二个立即执行函数后面没有加；导致了报错。具体原因经百度是这样的：

真正会导致上下行解析出问题的 token 有 5 个：括号，方括号，正则开头的斜杠，加号，减号。我还从没见过实际代码中用正则、加号、减号作为行首的情况，所以总结下来就是一句话：一行开头是括号或者方括号的时候加上分号就可以了，其他时候全部不需要

意思是括号开头会导致上下文解析错误，所以必须在之前加；

具体内容可以参考：

https://www.zhihu.com/question/20298345