如何在javascript中按ID合并多个对象数组

有了lodash，我觉得可读性更强了。

var arr1 = [{"memberID":"81fs","RatingCW":4.5},{"memberID":"80fs","RatingCW":4},{"memberID":"82fs","RatingCW":5},{"memberID":"83fs","RatingCW":3},{"memberID":"84fs","RatingCW":4.7}],
    arr2 = [{"memberID":"80fs","ratingWW":4},{"memberID":"81fs","ratingWW":4.5},{"memberID":"83fs","ratingWW":3},{"memberID":"82fs","ratingWW":5},{"memberID":"84fs","ratingWW":3.5}],
    arr3 = [{"memberID":"80fs","incoCW":4},{"memberID":"81fs","incoCW":4.5},{"memberID":"82fs","incoCW":5},{"memberID":"83fs","incoCW":3},{"memberID":"84fs","incoCW":4.5}],
    arr4 = [{"memberID":"80fs","incoWW":3},{"memberID":"81fs","incoWW":2.5},{"memberID":"82fs","incoWW":5},{"memberID":"83fs","incoWW":3},{"memberID":"84fs","incoWW":6.5}];
var merged = _(arr1)
  .concat(arr2, arr3, arr4)
  .groupBy("memberID")
  .map(_.spread(_.merge))
  .value();
console.log(merged);

<script src="https://cdn.jsdelivr.net/lodash/4.13.1/lodash.min.js"></script>

这是代码笔：http://codepen.io/kuhnroyal/pen/Wxzdmw

香草JS的方式，这是一个艰难的方式，花了几个小时才得到。

var arr1 = [{"memberID":"81fs","RatingCW":4.5},{"memberID":"80fs","RatingCW":4},{"memberID":"82fs","RatingCW":5},{"memberID":"83fs","RatingCW":3},{"memberID":"84fs","RatingCW":4.7}],
    arr2 = [{"memberID":"80fs","ratingWW":4},{"memberID":"81fs","ratingWW":4.5},{"memberID":"83fs","ratingWW":3},{"memberID":"82fs","ratingWW":5},{"memberID":"84fs","ratingWW":3.5}],
    arr3 = [{"memberID":"80fs","incoCW":4},{"memberID":"81fs","incoCW":4.5},{"memberID":"82fs","incoCW":5},{"memberID":"83fs","incoCW":3},{"memberID":"84fs","incoCW":4.5}],
    arr4 = [{"memberID":"80fs","incoWW":3},{"memberID":"81fs","incoWW":2.5},{"memberID":"82fs","incoWW":5},{"memberID":"83fs","incoWW":3},{"memberID":"84fs","incoWW":6.5}];
const arrs=[].concat(arr1,arr2,arr3,arr4);
const noDuplicate=arr=>[...new Set(arr)]
const allIds=arrs.map(ele=>ele.memberID);
const ids=noDuplicate(allIds);
const result=ids.map(id=>
    arrs.reduce((self,item)=>{
        return item.memberID===id?
        {...self,...item} : self
    },{})
)
console.log(result);

以下是使用lodash:的一些步骤

1. 将所有对象放入一个数组（_.flatform，然后_.groupby）
2. 将2d数组展平为'user'obj的1d数组（_.map，然后_.merge并应用于作为arg传入数组）

var arr1 =[
  { memberID : "81fs", RatingCW:4.5},
  { memberID : "80fs", RatingCW:4},
  { memberID : "82fs", RatingCW:5 },
  { memberID : "83fs", RatingCW:3},
  { memberID : "84fs", RatingCW:4.7}
];
var arr2 =[
  { memberID : "80fs", ratingWW: 4},
  { memberID : "81fs", ratingWW: 4.5},
  { memberID : "83fs", ratingWW: 3},
  { memberID : "82fs", ratingWW: 5},
  { memberID : "84fs", ratingWW: 3.5}
];
var arr3 =  [
  { memberID : "80fs", incoCW:4},
  { memberID : "81fs", incoCW:4.5},
  { memberID : "82fs", incoCW:5},
  { memberID : "83fs", incoCW:3},
  { memberID : "84fs", incoCW:4.5}
  ];
var arr4 =  [
  { memberID : "80fs", incoWW:3},
  { memberID : "81fs", incoWW:2.5 },
  { memberID : "82fs", incoWW:5 },
  { memberID : "83fs", incoWW:3 },
  { memberID : "84fs", incoWW:6.5 }
];
var a  = _.groupBy(_.flatten([arr1,arr2,arr3,arr4]), 'memberID');
var b = _.map(a, function(val){ return _.merge.apply(_,val) });    
console.log(b);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/1.2.1/lodash.min.js"></script>

arr1.map(a =>
    Object.assign({},a,
        arr2.find(b => b.memberID === a.memberID),
        arr3.find(c => c.memberID === a.memberID),
        arr4.find(d => d.memberID === a.memberID)
    )
)

这是最简单的代码。。。这基本上是一个oneliner解决方案。性能可能不是最好的，但对于小数据集来说效果很好。

您可以使用哈希表来正确引用结果数组。

由于对象中有引用memberID，所以我也使用未排序的数组。

 var arr1 = [{ memberID: "80fs", RatingCW: 4 }, { memberID: "81fs", RatingCW: 4.5 }, { memberID: "82fs", RatingCW: 5 }, { memberID: "83fs", RatingCW: 3 }, { memberID: "84fs", RatingCW: 4.7 }],
    arr2 = [{ memberID: "80fs", ratingWW: 4 }, { memberID: "81fs", ratingWW: 4.5 }, { memberID: "82fs", ratingWW: 5 }, { memberID: "83fs", ratingWW: 3 }, { memberID: "84fs", ratingWW: 3.5 }],
    arr3 = [{ memberID: "80fs", incoCW: 4 }, { memberID: "81fs", incoCW: 4.5 }, { memberID: "82fs", incoCW: 5 }, { memberID: "83fs", incoCW: 3 }, { memberID: "84fs", incoCW: 4.5 }],
    arr4 = [{ memberID: "80fs", incoWW: 3 }, { memberID: "81fs", incoWW: 2.5 }, { memberID: "82fs", incoWW: 5 }, { memberID: "83fs", incoWW: 3 }, { memberID: "84fs", incoWW: 6.5 }],
    merged = [];
[arr1, arr2, arr3, arr4].forEach(function (a) {
    a.forEach(function (b) {
        if (!this[b.memberID]) {
            this[b.memberID] = {};
            merged.push(this[b.memberID]);
        }
        Object.keys(b).forEach(function (k) {
            this[b.memberID][k] = b[k];
        }, this);
    }, this);
}, Object.create(null));
console.log(merged);

ES6用于未排序的数据。

 var arr1 = [{ memberID: "80fs", RatingCW: 4 }, { memberID: "81fs", RatingCW: 4.5 }, { memberID: "82fs", RatingCW: 5 }, { memberID: "83fs", RatingCW: 3 }, { memberID: "84fs", RatingCW: 4.7 }],
    arr2 = [{ memberID: "80fs", ratingWW: 4 }, { memberID: "81fs", ratingWW: 4.5 }, { memberID: "82fs", ratingWW: 5 }, { memberID: "83fs", ratingWW: 3 }, { memberID: "84fs", ratingWW: 3.5 }],
    arr3 = [{ memberID: "80fs", incoCW: 4 }, { memberID: "81fs", incoCW: 4.5 }, { memberID: "82fs", incoCW: 5 }, { memberID: "83fs", incoCW: 3 }, { memberID: "84fs", incoCW: 4.5 }],
    arr4 = [{ memberID: "80fs", incoWW: 3 }, { memberID: "81fs", incoWW: 2.5 }, { memberID: "82fs", incoWW: 5 }, { memberID: "83fs", incoWW: 3 }, { memberID: "84fs", incoWW: 6.5 }],
    merged = [];
[arr1, arr2, arr3, arr4].forEach((hash => a => a.forEach(b => {
    if (!hash[b.memberID]) {
        hash[b.memberID] = {};
        merged.push(hash[b.memberID]);
    }
    Object.assign(hash[b.memberID], b);
}))(Object.create(null)));
console.log(merged);