javascript - 如何在 Javascript 中从 Json 数组创建路线 Path？

Question

我有一个由一些随机城市名称组成的数组，另一个由各个城市的源和目的地组成的json对象数组，但是各个城市的这个路线数组不是按顺序排列的。我需要按照他们访问的顺序排列，我无法做出逻辑..请帮助..

城市数组(动态大小):

var CITIES = ["PARIS","LONDON","DELHI","SINGAPORE","DUBAI"]

路由的 Json 数组(随机序列):

var CITY_ROUTE = {"ROUTE":[
{"CURRENT_CITY":"PARIS","NEXT_CITY":"LONDON","PREVIOUS_CITY":"DUBAI",},
{"CURRENT_CITY":"DELHI","NEXT_CITY":"SINGAPORE","PREVIOUS_CITY":"LONDON"},
{"CURRENT_CITY":"LONDON","NEXT_CITY":"DELHI","PREVIOUS_CITY":"PARIS"},
{"CURRENT_CITY":"SINGAPORE","NEXT_CITY":"","PREVIOUS_CITY":"DELHI"},
{"CURRENT_CITY":"DUBAI","NEXT_CITY":"PARIS","PREVIOUS_CITY":""}
]};

/Required to Rearange the Json Object in Visiting sequence where Starting City will have null PREVIOUS_CITY value and Last City will have null  NEXT_CITY Value/


var CITY_ROUTE_IN_SEQUENCE = {"ROUTE":[
{"CURRENT_CITY":"DUBAI","NEXT_CITY":"PARIS","PREVIOUS_CITY":""}
{"CURRENT_CITY":"PARIS","NEXT_CITY":"LONDON","PREVIOUS_CITY":"DUBAI",},
{"CURRENT_CITY":"LONDON","NEXT_CITY":"DELHI","PREVIOUS_CITY":"PARIS"},
{"CURRENT_CITY":"DELHI","NEXT_CITY":"SINGAPORE","PREVIOUS_CITY":"LONDON"},
{"CURRENT_CITY":"SINGAPORE","NEXT_CITY":"","PREVIOUS_CITY":"DELHI"}
]};

Answer 1

var CITY_ROUTE = {
    "ROUTE": [
        {"CURRENT_CITY":"PARIS","NEXT_CITY":"LONDON","PREVIOUS_CITY":"DUBAI",},
        {"CURRENT_CITY":"DELHI","NEXT_CITY":"SINGAPORE","PREVIOUS_CITY":"LONDON"},
        {"CURRENT_CITY":"LONDON","NEXT_CITY":"DELHI","PREVIOUS_CITY":"PARIS"},
        {"CURRENT_CITY":"SINGAPORE","NEXT_CITY":"","PREVIOUS_CITY":"DELHI"},
        {"CURRENT_CITY":"DUBAI","NEXT_CITY":"PARIS","PREVIOUS_CITY":""}
    ]
};

var map = {};
var point = '';
CITY_ROUTE.ROUTE.forEach(r => {
    map[r.CURRENT_CITY] = r;
    if (!r.PREVIOUS_CITY) {
        point = r.CURRENT_CITY;
    }
});

CITY_ROUTE.ROUTE = [];
while(point) {
    CITY_ROUTE.ROUTE.push(map[point]);
    point = map[point].NEXT_CITY;
}
console.log(JSON.stringify(CITY_ROUTE));