如何从具有lodash的嵌套对象集合中获得唯一数组? [英] How can I get unique array from a collection of nested objects with lodash?

问题描述

我有以下收藏:

"items": [{
                "id": 1,
                "title": "Montrachet",
                "imageUrl": "http://winebuff.com.hk/products_image/3376-Ramonet-ChassagneMontrachetBlanc.jpg",
                "imageUrls": [
                    "http://winebuff.com.hk/products_image/3376-Ramonet-ChassagneMontrachetBlanc.jpg",
                    "http://media.riepenau.com/wines/17973_b.jpg",
                    "http://lorempixel.com/400/400/food/3"         
                ],
                "properties": [
                    {"description" : "Kırmızı Şaraplar Desc"},
                    {"region" :"Bordeaux"},
                    {"age": "16"},
                    {"producer" :"Kayra"},
                    {"grapeType":"Espadeiro"}

                ],
                "priceGlass": "1",
                "priceBottle": "2",
                "year": "1999"

            },

{
                "id": 2,
                "title": "Montrachet2",
                "imageUrl": "http://winebuff.com.hk/products_image/3376-Ramonet-ChassagneMontrachetBlanc.jpg",
                "imageUrls": [
                    "http://winebuff.com.hk/products_image/3376-Ramonet-ChassagneMontrachetBlanc.jpg",
                    "http://media.riepenau.com/wines/17973_b.jpg",
                    "http://lorempixel.com/400/400/food/3"         
                ],
                "properties": [
                    {"description" : "Kırmızı Şaraplar Desc"},
                    {"region" :"Bordeaux"},
                    {"age": "16"},
                    {"producer" :"Kayra"},
                    {"grapeType":"Chardonnay"}

                ],
                "priceGlass": "1",
                "priceBottle": "2",
                "year": "1999",
            }
] 

我想从该集合中获取独特的grapeTypes.返回数组的数组为["Chardonnay"，"Espadeiro"]

I want to grab unique grapeTypes from that collection. The returning array shold be ["Chardonnay","Espadeiro"]

用lodash做到最好的方法是什么?

What is the best way to do it with lodash?

推荐答案

我认为，采摘，映射和过滤器的这种组合应该可以做到:

I think this combination of pluck, map and filter should do it:

var result = _.chain(obj.items).pluck('properties').map(function(obj) {
    return _.filter(obj, function(prop) {
        return prop.grapeType;
    })[0].grapeType;
}).uniq().value();

console.log(result);

检查下面的演示运行.

// Code goes here

var obj = {
    items: [{
            "id": 1,
            "title": "Montrachet",
            "imageUrl": "http://winebuff.com.hk/products_image/3376-Ramonet-ChassagneMontrachetBlanc.jpg",
            "imageUrls": [
                "http://winebuff.com.hk/products_image/3376-Ramonet-ChassagneMontrachetBlanc.jpg",
                "http://media.riepenau.com/wines/17973_b.jpg",
                "http://lorempixel.com/400/400/food/3"
            ],
            "properties": [{
                    "description": "Kırmızı Şaraplar Desc"
                }, {
                    "region": "Bordeaux"
                }, {
                    "age": "16"
                }, {
                    "producer": "Kayra"
                }, {
                    "grapeType": "Espadeiro"
                }

            ],
            "priceGlass": "1",
            "priceBottle": "2",
            "year": "1999"

        },

        {
            "id": 2,
            "title": "Montrachet2",
            "imageUrl": "http://winebuff.com.hk/products_image/3376-Ramonet-ChassagneMontrachetBlanc.jpg",
            "imageUrls": [
                "http://winebuff.com.hk/products_image/3376-Ramonet-ChassagneMontrachetBlanc.jpg",
                "http://media.riepenau.com/wines/17973_b.jpg",
                "http://lorempixel.com/400/400/food/3"
            ],
            "properties": [{
                    "description": "Kırmızı Şaraplar Desc"
                }, {
                    "region": "Bordeaux"
                }, {
                    "age": "16"
                }, {
                    "producer": "Kayra"
                }, {
                    "grapeType": "Chardonnay"
                }

            ],
            "priceGlass": "1",
            "priceBottle": "2",
            "year": "1999",
        }
    ]
};


var result = _.chain(obj.items).pluck('properties').map(function(obj) {
    return _.filter(obj, function(prop) {
        return prop.grapeType;
    })[0].grapeType;
}).uniq().value();

document.write(JSON.stringify(result));

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/3.8.0/lodash.js"></script>

UPD .如果properties中可能缺少grapeType，则脚本应该为

UPD. If grapeType can be missing from properties then the script should be

var result = _.chain(obj.items).pluck('properties').map(function(obj) {
    return (_.filter(obj, function(prop) {
        return prop.grapeType;
    })[0] || {}).grapeType;
}).compact().uniq().value();

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