Lodash過濾器獨特的文件

Question

我怎樣才能篩選當前數據：

[{ 
    key: 'T1', 
    legs:[{ fno: 'W321',date: '2017-01-02 18:20:00.000+0200'}], 
    fare: { type: 'B', price: 25 } 
},{ 
    key: 'T1', 
    legs:[{ fno: 'W321', date: '2017-01-02T18:20:00.000+0200'}], 
    fare: { type: 'E', price: 23 } 
},{ 
    key: 'T1', 
    legs:[{ fno: 'W321', date: '2017-01-02T18:20:00.000+0200'}], 
    fare: { type: 'E', price: 20} 
}] 

我想按legs[0].fno，legs[0].date和fare.type，並保持各組中價格最低的項目。這是預期的結果：

[{ 
    key: 'T1', 
    legs:[{ fno: 'W321',date: '2017-01-02T18:20:00.000+0200'}], 
    fare: { type: 'B', price: 25} 
},{ 
    key: 'T1', 
    legs:[{ fno: 'W321',date: '2017-01-02T18:20:00.000+0200'}], 
    fare: { type: 'E', price: 20} 
}] 

Answer 1

使用_.groupBy()有回調使用_.minBy()通過創建一個字符串進行分組，然後_.map()各組的單個項目：

var data = [{"key":"T1","legs":[{"fno":"W321","date":"2017-01-02 18:20:00.000+0200"}],"fare":{"type":"B","price":25}},{"key":"T1","legs":[{"fno":"W321","date":"2017-01-02T18:20:00.000+0200"}],"fare":{"type":"E","price":23}},{"key":"T1","legs":[{"fno":"W321","date":"2017-01-02T18:20:00.000+0200"}],"fare":{"type":"E","price":20}}]; 
 

 
var result = _(data) 
 
    // group by the combined group keys 
 
    .groupBy(function(o) { 
 
    // extract all group keys and join them to a string 
 
    return _.at(o, ['key', 'legs[0].date', 'fare.type']).join(''); 
 
    }) 
 
    .map(function(group) { 
 
    // get the object object with the minimum fare.price 
 
    return _.minBy(group, 'fare.price'); 
 
    }) 
 
    .value(); 
 

 
console.log(result);

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