JavaScript-过滤出两个数组并取出重复项

Question

假设我有两个数组：

var sellersDatabase = [
  { name: 'Mark', start_date: '2017-06-27' },
  { name: 'Jane', start_date: '2017-06-27' }
];

var sellersAPICall = [
  { name: 'Mark', start_date: '2017-06-27' },
  { name: 'Joe', start_date: '2017-06-22' },
  { name: 'Steven', start_date: '2017-04-11' },
  { name: 'Jane', start_date: '2017-06-27' }
];

使用ES6或Lodash，如何获得未包含在第一个数组中的那些数组的差异？ 是的，我已经尝试过lodash的difference() 。

因此，我的预期输出将是：

var toInsertIntoDB = [
  { name: 'Joe', start_date: '2017-06-22' },
  { name: 'Steven', start_date: '2017-04-11' }
];

---

这样做：

javascript const toInsertToDB = _.difference(sellersDatabase, sellersAPICall); console.log(toInsertToDB);

输出：

[{ "name": "Mark", "start_date": "2017-06-27" }, { "name": "Jane", "start_date": "2017-06-27" }]

（当我想要相反的时候）

Answer 1

由于您要比较的是对象数组而不是原始类型，因此请使用_.differenceBy() ，并指出应通过哪个属性比较对象。 此外， sellersAPICall数组应为第一个（引用数组）。

 var sellersDatabase = [ { name: 'Mark', start_date: '2017-06-27' }, { name: 'Jane', start_date: '2017-06-27' } ]; var sellersAPICall = [ { name: 'Mark', start_date: '2017-06-27' }, { name: 'Joe', start_date: '2017-06-22' }, { name: 'Steven', start_date: '2017-04-11' }, { name: 'Jane', start_date: '2017-06-27' } ]; var result = _.differenceBy(sellersAPICall, sellersDatabase, 'name'); console.log(result); 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script> 

如果要比较2个属性，则可以使用将两个值连接在一起的回调函数：

 var sellersDatabase = [ { name: 'Mark', start_date: '2017-06-27' }, { name: 'Jane', start_date: '2017-06-27' } ]; var sellersAPICall = [ { name: 'Mark', start_date: '2017-06-27' }, { name: 'Joe', start_date: '2017-06-22' }, { name: 'Steven', start_date: '2017-04-11' }, { name: 'Jane', start_date: '2017-06-27' } ]; var result = _.differenceBy(sellersAPICall, sellersDatabase, function(o) { return o.name + '-' + o.start_date; }); console.log(result); 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js"></script>