javascript - 基于多个属性在数组中查找唯一对象 [英] javascript - find unique objects in array based on multiple properties

问题描述

我需要根据以下2个属性从数组中找到唯一对象。当class和fare匹配时，我需要提取唯一值并将它们放入结果数组中。

I need to find unique objects from array based on 2 properties as below. When "class" and "fare" match, I need to pull out unique values and get them in results array.

来源：

var arr = [{class:"second", fare: "a"}, 
 {class:"second", fare: "b"},
 {class:"first", fare: "a"},
 {class:"first", fare: "a"},
 {class:"second", fare: "a"},
 {class:"first", fare: "c"}
]

预期结果：

var result = [{class:"second", fare: "a"},
 {class:"second", fare: "b"},
 {class:"first", fare: "a"},
 {class:"first", fare: "c"}
]

我查看了SO并找到了答案基于一个属性进行过滤（按属性创建唯一对象数组 ），但找不到基于2个属性可以做什么。

I looked over in SO and was able to find answer which is filtered based on one property (Create array of unique objects by property), but couldn't find which could do based on 2 properties.

推荐答案

你可以构建一个组合哈希表的ned键是给定数组的过滤器。

You could build a combined key for the hash table an filter the given array.

var arr = [{ class: "second", fare: "a" }, { class: "second", fare: "b" }, { class: "first", fare: "a" }, { class: "first", fare: "a" }, { class: "second", fare: "a" }, { class: "first", fare: "c" }],
    result = arr.filter(function (a) {
        var key = a.class + '|' + a.fare;
        if (!this[key]) {
            this[key] = true;
            return true;
        }
    }, Object.create(null));

console.log(result);

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