javascript - 如何将一个 JSON 行重新映射到分层 JSON？

Question

我现在遇到了一个令我心痛的难题，我想将 [01] JSON 转换为 [02]。

[01] JSON :

{locations: [
    {
        country: "Australia",
        area: "NSW",
        city: "Gordon"
    },
    {
        country: "Australia",
        area: "NSW",
        city: "Chatswood"
    }
]};

[02] JSON :

{countries: [
    {
        name: "Australia",
        areas: [
            {
                 name: "NSW",
                 cities: [
                      {
                           name: "Gordon"
                      },
                      {
                           name: "Chatswood"
                      }
                 ]
            }
        ]
    } 
]}

Answer 1

由于您要进行大量查找，我建议使用对象集合而不是使用数组的最终结构。然后，您可以将其转换为最终结构或修改代码以按原样使用它。

var countries = {};
for (var i=0, loc; loc = locations[i]; i++) {
    if (!countries[loc.country]) countries[loc.country] = {};
    if (!countries[loc.country][loc.area]) countries[loc.country][loc.area] = [];
    countries[loc.country][loc.area].push(loc.city);
}
alert(JSON.stringify(countries));