js 对象数组去重

方法一:利用filter

var arr=[{id:1,name:'bob'},{id:1,name:'bob'},{id:1,name:'bob'},{id:1,name:'lucy'},{id:1,name:'lucy'},{id:2,name:'lucy'},{id:2,name:'张三'}]
//去掉相同id的项目
var arr1=arr.filter(function(element,index,self){
  return self.findIndex(el=>el.id==element.id)===index
})
//封装成方法,通过某个属性去重
function filterRepeat(arr,prop){
  return arr.filter(function(element,index,self){
    return self.findIndex(el=>el[prop]==element[prop])===index
  })
}
//自定义去重方法
function filterRepeat2(arr,compareFn){
  return arr.filter(function(element,index,self){
    return self.findIndex(el=>compareFn(el,element))===index
  })
}
//加载到数组原型上
Array.prototype.filterRepeat=function(){
      if(typeof arguments[0]=='string')  return filterRepeat(this,arguments[0])
      return filterRepeat2(this,arguments[0])
}
//test 通过name属性去重
var newArr=arr.filterRepeat('name')
console.log(newArr)
var newArr2=arr.filterRepeat(function(a,b){return a.id==b.id&&a.name==b.name})
console.log(newArr2)

方法二:利用reduce

var arr=[{id:1,name:'bob'},{id:1,name:'bob'},{id:1,name:'bob'},{id:1,name:'lucy'},{id:1,name:'lucy'},{id:2,name:'lucy'},{id:2,name:'张三'}]
var arr1=arr.reduce(function(prev,element){
  if(!prev.find(el=>el.id==element.id)) {
    prev.push(element)
  }
  return prev
},[])