代码片段收集

else-if

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// 过去 else-if 形式
function customerValidation(customer) {
  if (!customer.email) {
    return error('email is require')
  } else if (!customer.login) {
    return error('login is required')
  } else if (!customer.name) {
    return error('name is required')
  } else {
    return customer
  }
}
// ES6 中使用三目运算符
const customerValidation = customer =>
  !customer.email ? error('email is required') :
  !customer.login ? error('login is required') :
  !customer.name  ? error('name is required')
                  : customer

利用arguments

from: Interviewing a front-end developer:

实现log函数

输出参数的值:

  • log('hello'); // hello
  • log('hello', 'world');// hello world

输出自定义字符串+参数:

  • logWith('hello', 'world'); // (app) hello world

兼容bind

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Function.prototype.bind = Function.prototype.bind || function(context) {  
  var self = this;
  return function(){
    return self.apply(context, arguments);
  };
}

touch 事件模拟 scroll 事件

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'touchstart': 'handleTouchStart',
'touchmove': 'handleTouchMove',
'touchend': 'handleTouchEnd',
 
handleTouchStart: function(event) {
  this.startClientY = event.touches[0].clientY
  this.startScrollTop = _scroll_dom.scrollTop()
},
handleTouchMove: function(event) {
  this.currentClientY = event.touches[0].clientY
  this.currentScrollTop = _scroll_dom.scrollTop()
  // if handleTouchEnd is not triggered
  clearTimeout(this.touchTimer)
  this.touchTimer = setTimeout(function() {
    self.handleTouchEnd()
  }, 5)
},
handleTouchEnd: function() {
  clearTimeout(this.touchTimer)
  var isSwipeUp = this.currentClientY < this.startClientY
  var isNoScroll = this.currentScrollTop === this.startScrollTop
  if (isSwipeUp && isNoScroll) {
    doSomething()
  }
}

从 url 中获取参数值

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function getUrlParam(name) {
  return decodeURIComponent((new RegExp('[?|&]' + name + '=' + '([^&;]+?)(&|#|;|$)').exec(location.search) || [null, ''])[1].replace(/\+/g, '%20')) || null;
}