嘗試使用ES6過濾和扁平化嵌套對象

Question

我是全新的，以ES6的數組，我有，看起來像對象的數組：

locations: [ 
    { 
    "is_moving": true, 
    "uuid": "82fa9dda-e57b-4b3f-99a0-a1db98ae4a19", 
    "timestamp": "2017-08-05T04:48:25.526Z", 
    "odometer": 0, 
    "sample": true, 
    "coords": { 
     "latitude": 32.7323862, 
     "longitude": -117.1939315, 
     "accuracy": 1000, 
     "speed": -1, 
     "heading": -1, 
     "altitude": -1 
    }, 
    "activity": { 
     "type": "in_vehicle", 
     "confidence": 54 
    }, 
    "battery": { 
     "is_charging": false, 
     "level": 0.5 
    }, 
    "extras": {} 
    }, 
    { 
    "event": "motionchange", 
    "is_moving": true, 
    "uuid": "57a0146a-28b9-4baf-86de-e037843c2d32", 
    "timestamp": "2017-08-05T04:48:25.526Z", 
    "odometer": 0, 
    "coords": { 
     "latitude": 32.7323862, 
     "longitude": -117.1939315, 
     "accuracy": 1000, 
     "speed": -1, 
     "heading": -1, 
     "altitude": -1 
    }, 
    "activity": { 
     "type": "in_vehicle", 
     "confidence": 54 
    }, 
    "battery": { 
     "is_charging": false, 
     "level": 0.5 
    }, 
    "extras": {} 
    } 
] 

我想結束了是：

locations: [ 
    { 
    "timestamp": "2017-08-05T04:48:25.526Z", 
    "odometer": 0, 
    "latitude": 32.7323862, 
    "longitude": -117.1939315, 
    "accuracy": 1000, 
    "speed": -1, 
    "heading": -1, 
    "altitude": -1 
    }, 
    { 
    "timestamp": "2017-08-05T04:48:25.526Z", 
    "odometer": 0, 
    "latitude": 32.7323862, 
    "longitude": -117.1939315, 
    "accuracy": 1000, 
    "speed": -1, 
    "heading": -1, 
    "altitude": -1 
    } 
] 

所以我知道我可以做（感謝https://stackoverflow.com/a/39333664/994275）過濾掉，我不想鍵/值對：

locations.map(({ timestamp, odometer, coords }) => ({ timestamp, odometer, coords })) 

，我知道我可以做（感謝https://stackoverflow.com/a/33037683/994275）扁平化的對象：

Object.assign(
    {}, 
    ...function _flatten(location) { 
    return [].concat(...Object.keys(location) 
     .map(k => 
     typeof location[k] === 'object' ? 
      _flatten(location[k]) : 
      ({[k]: location[k]}) 
    ) 
    ); 
    }(location) 
) 

但我試圖將兩者結合起來，並慘遭失敗。我在地圖中添加了平鋪，但這只是返回一個未定義的數組。

我確定有一個簡單的解決方法，但它在這一點上無法解決。任何幫助將不勝感激！

這裏是工作（感謝誰似乎已經消除了他們的意見的用戶）：

let newLocations = locations.map(({ is_moving, uuid, timestamp, odometer, coords }) => ({ is_moving, uuid, timestamp, odometer, coords })); 
let test = newLocations.map((location) => { 
    return Object.assign(
    {}, 
    ...function _flatten(location) { 
     return [].concat(...Object.keys(location) 
     .map(k => 
      typeof location[k] === 'object' ? 
      _flatten(location[k]) : 
      ({[k]: location[k]}) 
     ) 
    ); 
    }(location) 
) 
}); 

有沒有辦法凝聚過濾和扁平化？

Answer 1

function body of an arrow function有兩種語法：一種帶有「塊體」，另一種帶有「簡明主體」。在使用「塊體」時，如果不想返回undefined，則必須使用大括號{ }在塊中包含所包含的語句，並且需要明確的return語句。

您可以將兩個操作結合成一個單一map並使用「簡潔的身體」語法：

let newLocations = locations.map(({ is_moving, uuid, timestamp, odometer, coords }) => 
    Object.assign(
    {}, 
    ...function _flatten(location) { 
     return [].concat(...Object.keys(location) 
     .map(k => 
      typeof location[k] === 'object' ? 
      _flatten(location[k]) : 
      ({[k]: location[k]}) 
     ) 
    ); 
    }({ is_moving, uuid, timestamp, odometer, coords }) 
) 
);