从数组中删除重复项 [英] Remove duplicates form an array

问题描述

我有一个看起来像这样的对象数组:

I have an array of objects that looks like this:

var array = [
    {id:123, value:"value1", name:"Name1"},
    {id:124, value:"value2", name:"Name1"},
    {id:125, value:"value3", name:"Name2"},
    {id:126, value:"value4", name:"Name2"}
    ...
];

如您所见，有些名称是重复的.我想获得一个只有名称的新数组，但如果某些名称重复，我不想再次添加它.我想要这个数组:

As you can see, some names are repeated. I want to get a new array with names only, but if some name repeats I don't want to add it again. I want this array:

var newArray = ["Name1", "Name2"];

我正在尝试使用 map 来做到这一点:

I'm trying to do this with map:

var newArray = array.map((a) => {
    return a.name;
});

但问题是这会返回:

newArray = ["Name1", "Name1", "Name2", "Name2"];

如何在 map 中设置一些条件，使其不返回已存在的元素?我想用 map 或其他一些 ECMAScript 5 或 ECMAScript 6 功能来做到这一点.

How can I set some condition inside map, so it won't return an element that already exists? I want to do this with map or some other ECMAScript 5 or ECMAScript 6 feature.

推荐答案

使用 ES6，你可以使用 Set 用于唯一值，仅映射对象的名称后.

With ES6, you could use Set for unique values, after mapping only the names of the objects.

该提案使用传播语法... 用于收集新数组中的项目.

This proposal uses a spread syntax ... for collecting the items in a new array.

const array = [{ id: 123, value: "value1", name:"Name1" }, { id: 124, value: "value2", name: "Name1" }, { id: 125, value: "value3", name: "Name2" }, { id: 126, value: "value4", name: "Name2" }],
      names = [...new Set(array.map(a => a.name))];

console.log(names);

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