let obj = {
  part1: {
    name: '零一',
    age: 23
  }
}

// 解構(gòu)
const { part1: { name, age } } = obj
// 使用
console.log(name, age)  // 零一  23

// .... 省略

const { part1: { name, age } } = obj
console.log(part1)   // Uncaught ReferenceError: part1 is not defined

// .... 省略

const { part1: { name, age }, part1 } = obj
console.log(part1)   // {name: "零一", age: 23}

const myMoney = 1000000000000

const myMoney = 1_000_000_000_000

console.log(myMoney)  // 1000000000000

function demo () {
  return 1
  console.log('我是零一')
  return 2
}

console.log(demo())   // 1

function demo () {
  try {
    return 1
  } catch (err) {
    console.log(err)
    return 2
  } finally {
    return 3
  }
}

console.log(demo())   // 返回什么？？

function demo () {
  try {
    return 1
  } catch (err) {
    console.log(err)
    return 2
  } finally {
    try {
      return 3
    } finally {
      return 4
    }
  }
}

console.log(demo())  // 返回 4

function firstFunction() { secondFunction(); } 
function secondFunction() { thridFunction(); } 
function thridFunction() { console.log(new Error().stack); }

firstFunction();

//=> Error 
//  at thridFunction (<anonymous>:2:17) 
//  at secondFunction (<anonymous>:5:5) 
//  at firstFunction (<anonymous>:8:5) 
//  at <anonymous>:10:1

function hash () {
  let s = ''
  const strs = [
    'a', 'b', 'c', 'd', 'e', 'f', 'g', 
    'h', 'i', 'j', 'k', 'l', 'm', 'n', 
    'o', 'p', 'q', 'r', 's', 't', 'u', 
    'v', 'w', 'x', 'y', 'z', '0', '1', 
    '2', '3', '4', '5', '6', '7', '8',
    '9',
  ]
  for(let i = 0; i < 10; i++) {
    s += strs[Math.floor(Math.random() * strs.length)]
  }
  return s
}

hash()  // 'www7v2if9r'

const str = Math.random().toString(36).substr(2, 10);
console.log(str);   // 'w5jetivt7e'

<div id="zero2one"></div>

const el = document.getElementById('zero2one')  
console.log(el)   // <div id="zero2one"></div>

console.log(zero2one)   // <div id="zero2one"></div>