使用_.differenceBy从另一个对象数组中删除一个对象数组中的项 [英] Remove items from one array of objects from another array of objects with _.differenceBy

问题描述

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，其中包含被告列表中未包含的来自被告列表的值.如何使用lodash或标准JS数组函数简单地做到这一点?我正在查看lodash的 _.differenceBy ，因为它具有迭代器，但是我还不太清楚怎么做.

I need to create an array that has values from defendantList that are not contained in dismissedDefendants. How can I do that simply, either with lodash or a standard JS array function? I'm looking at lodash's _.differenceBy, since it has an iteratee, but I can't quite figure out how.

更新:此示例中所需的最终结果只是对象不匹配的数组:

UPDATE: the desired end result in this example is just an array with the non-matching object:

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

谢谢.

推荐答案

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() 和 设置 :

And an ES6 solution based on Array.prototype.filter() and 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);

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