从Javascript数组中删除等效但唯一的对象

Question

我有一个类似于以下对象的数组:

var routeArr = [
    {start: 1, end: 2},
    {start: 1, end: 3},
    {start: 1, end: 4},
    {start: 2, end: 1},
    {start: 3, end: 1},
    {start: 4, end: 1}
];

这些对象代表线的起点和终点,{start: 1, end: 2}因此{start: 2, end: 1}代表同一条线.

我试图从数组中删除所有重复的行,并找不到有效或优雅的方法来做到这一点.我已经尝试了一个嵌套循环但是,我被告知这是不好的做法(我的实现有错误,而且它只是丑陋).

for(var i = 0, numRoutes = routeArr.length; i < numRoutes; i++) {
    var primaryRoute = routeArr[i];

    for(var j = 0; j < numRoutes; j++) {
        var secondRoute = routeArr[j];

        if(primaryRoute.start === secondRoute.end && primaryRoute.end === secondRoute.start) {
            routeArr.splice(j, 1);
            continue;
        }
    }
}

有人可以提供建议吗？

Answer 1

在javascript中创建一个对象/映射并保留唯一对象的索引，将“min(start,end):max(start,end)”存储为键，将索引存储为值。这是您的问题在 javascript 中的实现：

// your initial array
var routeArr = [
    {start: 1, end: 2},
    {start: 1, end: 3},
    {start: 1, end: 4},
    {start: 2, end: 1},
    {start: 3, end: 1},
    {start: 4, end: 1}
];

// map where we will store key => value where key is a joined start,end of your array's item and value is an item index 
var keyToRouteIndexMap = {};

for (var i in routeArr){
    // calculating min and max from start and end to understand {start:1, end:2} and {start:2, end:1} object as duplicates
    var min = Math.min(routeArr[i].start,routeArr[i].end);
    var max = Math.max(routeArr[i].start,routeArr[i].end);
    // unique key 
    var key = min+':'+max;
    if (!keyToRouteIndexMap.hasOwnProperty(key)){
        keyToRouteIndexMap[key] = i;
    }
}

for(var key in keyToRouteIndexMap){
    if(keyToRouteIndexMap.hasOwnProperty(key)){
        console.log(routeArr[keyToRouteIndexMap[key]]);
    }
}