手写代码

function debonce(fn, wait) {
  var timer
  return function() {
    clearTimeout(timer)
    timer = setTimeOut(fn, wait)
  }
}

function throttle(fn, delay) {
  let lastTime = Date.now()
  let timerId
  return function(...args) {
    const now = Date.now()
    const context = this
    if (now - lastTime > delay) {
      lastTime = now
      fn.apply(context, args)
    } else {
      clearTimeout(timerId)
      timerId = setTimeout(function() {
        fn.apply(context, args)
      }, delay)
    }
  }
}

// Set
Array.prototype.unique = function() {
  // return [...new Set(this)]
  return Array.from(new Set(this))
}

var a = [1,2,3,1]
a.unique()

// filter + indexOf
function unique(arr) {
  if (!Array.isArray(arr)) throw new Error('must be array')
  return arr.filter((value, index, self) => self.indexOf(value) === index)
}

unique([1,2,1])

function newOp(ctor, ...args) {
  if (typeof ctor !== 'function') {
    throw 'params must be function'
  }
  const newObj = Object.create(ctor.prototype)
  const result = crot.apply(newObj, args)
  
  const isObject = typeof result === 'object' && result !== null
  const isFunction = typeof result === 'function'
  if (isObject || isFunction) return result
  return newObj
}

class Parent {
  constructor(name) {
    this.name = name
  }
  myName() {
    console.log(this.name)
  }
}

class Son extends Parent{
  constructor(name, age) {
    super(name)
    this.age = age
  }

  myAge() {
    console.log(this.age)
  }
}

function Parent(name) {
  this.name = name
}

Parent.prototype.myName = function() {
  console.log(this.name)
}

function Son(name, age) {
  Parent.apply(this, arguments)
  this.age = age
}

// Son.prototype = Object.create(Parent.prototype)
Son.prototype = new Parent()
Son.prototype.constructor = Son

Son.prototype.myAge = function() {
  console.log(this.age)
}

let url = 'http://www.domain.com/?user=anonymous&id=123&id=456&city=%E5%8C%97%E4%BA%AC&enabled';
parseParam(url)
/* 结果
{ user: 'anonymous',
  id: [ 123, 456 ], // 重复出现的 key 要组装成数组，能被转成数字的就转成数字类型
  city: '北京', // 中文需解码
  enabled: true, // 未指定值得 key 约定为 true
}
*/

let url = 'http://www.domain.com/?user=anonymous&id=123.22&id=456&city=%E5%8C%97%E4%BA%AC&enabled';

function parseParam(url) {
  var paramStr = url.split('?')[1].split('&')
  var result = {}
  paramStr.forEach((param) => {
    if (/=/.test(param)) {
      var v = decodeURIComponent(param.split('=')[1])
      v = /^\d+/.test(v) ? +v : v
      var k = param.split('=')[0]
      if (result[k]) {
        result[k] = [].concat(result[k], v)
      } else {
        result[k] = v
      }
    } else {
      result[param] = true
    }
  })
  return result
}

parseParam(url)