使用Lodash無法實現JSON結構

Question

我仍然很難找出要使用的方法。 我正在使用提供給我的較早的lodash解決方案，以便可以了解Lodash的工作方式。 當前正在發生的事情是，輸出變成了一個對象，而deviceModels變成了鍵。 我期待這種輸出

[ { "deviceModel": "Canon450MX", "overallTotal": 75, "deviceCount": 3, "dates": [ { "date": "2014-09-01T05:00:00Z", "deviceModel": "Canon450MX", // This can be removed "totalInchesPrinted": 30 }, { "date": "2014-09-01T06:00:00Z", "deviceModel": "Canon450MX", // This can be removed "totalInchesPrinted": 180 }, { "date": "2014-09-01T06:00:00Z", "deviceModel": "Canon450MX", // This can be removed "totalInchesPrinted": 45 } ] }, { "deviceModel": "Canon9000ST", "overallTotal": 645, "deviceCount": 3, "dates": [ { "date": "2014-09-01T06:00:00Z", "deviceModel": "Canon9000ST", // This can be removed "totalInchesPrinted": 600 }, { "date": "2014-09-01T06:00:00Z", "deviceModel": "Canon9000ST", // This can be removed "totalInchesPrinted": 45 } ] }, { "deviceModel": "HPDeskjet", "overallTotal": 76, "deviceCount": 3, "dates": [ { "date": "2014-09-01T05:00:00Z", "deviceModel": "HPDeskjet", // This can be removed "totalInchesPrinted": 40 }, { "date": "2014-09-01T06:00:00Z", "deviceModel": "HPDeskjet", // This can be removed "totalInchesPrinted": 6 }, { "date": "2014-09-01T07:00:00Z", "deviceModel": "HPDeskjet", // This can be removed "totalInchesPrinted": 30 } ] } ]

但是輸出是這樣生成的

{ "Canon450MX": [ { "date": "2014-09-01T05:00:00Z", "deviceModel": "Canon450MX", "totalInchesPrinted": 30 }, { "date": "2014-09-01T06:00:00Z", "deviceModel": "Canon450MX", "totalInchesPrinted": 180 }, { "date": "2014-09-01T07:00:00Z", "deviceModel": "Canon450MX", "totalInchesPrinted": 45 } ], "Canon9000ST": [ { "date": "2014-09-01T06:00:00Z", "deviceModel": "Canon9000ST", "totalInchesPrinted": 600 }, { "date": "2014-09-01T07:00:00Z", "deviceModel": "Canon9000ST", "totalInchesPrinted": 45 } ], "HPDeskjet": [ { "date": "2014-09-01T05:00:00Z", "deviceModel": "HPDeskjet", "totalInchesPrinted": 40 }, { "date": "2014-09-01T06:00:00Z", "deviceModel": "HPDeskjet", "totalInchesPrinted": 6 }, { "date": "2014-09-01T07:00:00Z", "deviceModel": "HPDeskjet", "totalInchesPrinted": 30 } ] }

這是我的JS小提琴-http: //jsfiddle.net/ohgenLr5/2/

另外，我想知道如何根據當天的唯一序列號添加totalTotal和deviceCount（如上所示）。

任何幫助將不勝感激！

謝謝！

Answer 1

您只需要在groupBy之后再做一張額外的map就可以得到想要的結構，使用reduce可以得到打印的總英寸數之和。

var data = _.chain(list[0].dates)
    .map(transformDeviceModels)
    .flatten()
    .sortBy('deviceModel')
    .groupBy('deviceModel')
    .map(function(printers, model) {
        return {
            deviceModel: model,
            overallTotal: _.reduce(printers, function(sum, printer) {
                return sum + printer.totalInchesPrinted;
            }, 0),
            deviceCount: printers.length,
            dates: printers
        };
    })
    .value();

現場演示