javascript - 在循环中创建对象

Question

我有一个包含公司和国家/地区的 json 文件。创建对象最正确的方法是什么。循环遍历所有国家，我必须计算有多少家公司与特定国家相关，才能得到结果对象，大致格式如下:

country = {
   USA: 13, 
   Germany: 11,
   Belgia: 3
}

Answer 1

您可以尝试这样的操作:(使用编辑之前问题中的对象数据。)

var jsondata = {"list":[{"name":"Photolist","location":{"name":"Poland","code":"PL"},"partners":[{"name":"Oloo","value":30},{"name":"Flashset","value":87}]},{"name":"Mymm","location":{"name":"Ukraine","code":"UA"},"partners":[{"name":"Photojam","value":57},{"name":"Divavu","value":82},{"name":"Quinu","value":18}]},{"name":"Yata","location":{"name":"United States","code":"US"},"partners":[{"name":"Meetz","value":72}]},{"name":"Brainbox","location":{"name":"Norway","code":"NO"},"partners":[{"name":"Divavu","value":42}]},{"name":"Flashpoint","location":{"name":"Sweden","code":"SE"},"partners":[{"name":"Babbleopia","value":53},{"name":"Buzzdog","value":70},{"name":"Voolia","value":20}]},{"name":"Photospace","location":{"name":"Poland","code":"PL"},"partners":[{"name":"Yakitri","value":81},{"name":"Divavu","value":85},{"name":"Skimia","value":12},{"name":"Meeveo","value":27}]},{"name":"Realfire","location":{"name":"Poland","code":"PL"},"partners":[{"name":"Topicshots","value":81}]}]};

var countries = {};
jsondata.list.forEach(function (elem) {
    if (elem.location.name in countries) { 
        countries[elem.location.name]++;
    } else {
        countries[elem.location.name] = 1; 
    }
});

console.log(countries);