1. 返回一个已排序的可循环对象

        
        

          
123456
          
var dist = {'a': ['A', 3], 'c': ['B', 4], 'b': ['C', 2], 'e': ['A', 2.7], 'd': ['B', 1]}

Object.keys(dist).reduce((r, i) => {
	if (r[dist[i][1]] == undefined || r[dist[i][1]] > i) r[dist[i][1]] = i
	return r
}, {})
        
      

2. 最简单的方式实现依赖注入

        
        

          
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/**
 * Constructor DependencyInjector
 * @param {Object} - object with dependencies
 */
class DI {

  constructor(dependency) {
    this.dependency = dependency
  }

  inject(func) {
    let deps = /^[^(]+\(([^)]+)/.exec(func.toString())

    // 构建参数绑定数组
    deps = !deps ? [] : deps[1].split(/\s?,\s?/).map(dep => this.dependency[dep])
    return function () {
      return func.apply(this, deps)
    }
  }
}
        
      

3. 实现一个字符串形式的 IP 地址，转为 INT 整型保存，及逆转方法

        
        

          
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const ip2int = function(ip) {
  var num = 0
  ip = ip.split(".")
  num = Number(ip[0]) * 256 * 256 * 256 + Number(ip[1]) * 256 * 256 + Number(ip[2]) * 256 + Number(ip[3])
  num = num >>> 0
  return num
}
/**
 * 数字转ip
 * @param num
 * @returns {string|*}
 * @private
 */
/*global _int2ip(num: number) */
const int2iP = function(num) {
  var str
  var tt = new Array()
  tt[0] = (num >>> 24) >>> 0
  tt[1] = ((num << 8) >>> 24) >>> 0
  tt[2] = (num << 16) >>> 24
  tt[3] = (num << 24) >>> 24
  str = String(tt[0]) + "." + String(tt[1]) + "." + String(tt[2]) + "." + String(tt[3])
  return str
}