JavaScript二维数组变换：第一维和第二维互换

gistfile1.js

var src = [
    {
        "duration": [
            0, 
            "01:10:10"
        ], 
        "traffic": [
            {
                "customer": {
                    "tags": "!VIP"
                }, 
                "sum": 10,
                "per": 0.1
            }, 
            {
                "customer": {
                    "tags": "!customer"
                }, 
                "sum": 20,
                "per": 0.2
            }, 
            {
                "customer": {
                    "tags": "!staff"
                }, 
                "sum": 30,
                "per": 0.3
            }, 
            {
                "customer": {
                    "tags": null
                }, 
                "sum": 40,
                "per": 0.4
            }
        ],
        "total": 100
    }, 
    {
        "duration": [
            4210, 
            "03:20:20"
        ], 
        "traffic": [
            {
                "customer": {
                    "tags": "!VIP"
                }, 
                "sum": 100,
                "per": 0.1
            }, 
            {
                "customer": {
                    "tags": "!customer"
                }, 
                "sum": 200,
                "per": 0.2
            }, 
            {
                "customer": {
                    "tags": "!staff"
                }, 
                "sum": 300,
                "per": 0.3
            }, 
            {
                "customer": {
                    "tags": null
                }, 
                "sum": 400,
                "per": 0.4
            }
        ],
        "total": 1000
    }
]

var dst = ['!VIP', '!customer', '!staff', null].map(function(tags){
    var value =  src.map(function(item){
        var traffic = item.traffic.filter(function(traffic){
            return traffic.customer.tags === tags;
        });
        
        return {
            'duration': item.duration,
            'sum': traffic.length ? traffic[0].sum : 0
        };
    })
    
    var total = value.reduce(function(a,b){return a+b.sum}, 0);
    value.forEach(function(item){
        item.per = Math.round(item.sum*100/total)/100;
    })
    
    return {
        'customer': {
            'tags': tags
        },
        'traffic': value,
        'total': total
    }
})

console.dir(dst);
console.log(JSON.stringify(dst));