javascript - 使用 _.differenceBy 从一个对象数组中删除另一个对象数组中的项目

Question

我有两个对象数组:

var defendantList = [
  {
    label: "Joe BLow"
    value: "Joe Blow"
  },
  {
    label: "Sam Snead"
    value: "Sam Snead"
  },
  {
    label: "John Smith"
    value: "John Smith"
  },
];

var dismissedDefendants = [
  {
    date: 'someDateString',
    value: "Joe Blow"
  },
  {
    date: "someOtherDateString",
    value: "Sam Snead"
  }
];

我需要创建一个数组，其中包含 defendentList 中未包含在 dismissedDefendants 中的值。我怎样才能简单地做到这一点，无论是使用 lodash 还是标准的 JS 数组函数？我在看 lodash 的 _.differenceBy ，因为它有一个迭代器，但我不太清楚如何。

更新:此示例中所需的最终结果只是一个包含不匹配对象的数组:

  var newArray = [
      {
        label: "John Smith"
        value: "John Smith"
      },
    ];

谢谢。

Answer 1

使用_.differenceBy():

_.differenceBy(defendantList, dismissedDefendants, 'value');

var defendantList = [
  {
    label: "Joe BLow",
    value: "Joe Blow"
  },
  {
    label: "Sam Snead",
    value: "Sam Snead"
  },
  {
    label: "John Smith",
    value: "John Smith"
  },
];

var dismissedDefendants = [
  {
    date: 'someDateString',
    value: "Joe Blow"
  },
  {
    date: "someOtherDateString",
    value: "Sam Snead"
  }
];

var result = _.differenceBy(defendantList, dismissedDefendants, 'value');

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.2/lodash.min.js"></script>

以及基于 Array.prototype.filter() 的 ES6 解决方案和 Set :

defendantList.filter(function({ value }) { 
  return !this.has(value); // keep if value is not in the Set
}, new Set(dismissedDefendants.map(({ value }) => value))); //create a Set of unique values in dismissedDefendants and assign it to this

var defendantList = [
  {
    label: "Joe BLow",
    value: "Joe Blow"
  },
  {
    label: "Sam Snead",
    value: "Sam Snead"
  },
  {
    label: "John Smith",
    value: "John Smith"
  },
];

var dismissedDefendants = [
  {
    date: 'someDateString',
    value: "Joe Blow"
  },
  {
    date: "someOtherDateString",
    value: "Sam Snead"
  }
];

var result = defendantList.filter(function({ value }) { 
  return !this.has(value); 
}, new Set(dismissedDefendants.map(({ value }) => value)));

console.log(result);