javascript - 在每次地圖迭代的開頭添加對象

Question

所以，讓我們假設我有這個：

var officers = [
  { id: 20, name: 'Captain', lastName: 'Piett' },
  { id: 24, name: 'General', lastName: 'Veers'  },
  { id: 56, name: 'Admiral', lastName: 'Ozzel'  },
  { id: 88, name: 'Commander', lastName: 'Jerjerrod'  }
];

如果我這樣做： var officersIds = officers.map(x => [x.name, x.lastName]); 結果officersIds是會是這樣的：

[ "Captain", "Piett" ], [ "General", "Veers" ], [ "Admiral", "Ozzel" ], [ "Commander", "Jerjerrod" ]

對？

所以，我需要做的是在每次地圖迭代上放置一個對象，因此輸出現在是這樣的，例如：

[["x", "y"], [ "Captain", "Piett" ]], 
[["x", "y"], [ "General", "Veers" ]],  
[["x", "y"], [ "Admiral", "Ozzel" ]], 
[["x", "y"], [ "Commander", "Jerjerrod" ]]

為什么我需要這個？ 最好不要問;) 但這是一個復雜的問題，如果你幫我解決這個簡單的問題，我可以將你的解決方案轉移到我的復雜問題上。

重要提示：有沒有辦法在一行中做到這一點？

Answer 1

var officers = [
  { id: 20, name: 'Captain', lastName: 'Piett' },
  { id: 24, name: 'General', lastName: 'Veers'  },
  { id: 56, name: 'Admiral', lastName: 'Ozzel'  },
  { id: 88, name: 'Commander', lastName: 'Jerjerrod' },
];

officers.unshift({ name: x, lastName: y });

var officersIds = officers.map(x => [x.name, x.lastName]);

或者

var officers = [
      { id: 20, name: 'Captain', lastName: 'Piett' },
      { id: 24, name: 'General', lastName: 'Veers'  },
      { id: 56, name: 'Admiral', lastName: 'Ozzel'  },
      { id: 88, name: 'Commander', lastName: 'Jerjerrod' },
    ];


    var officersIds = officers.map(x => [x.name, x.lastName]);

    officersIds.unshift(["x", "y" ]);

Answer 2

用地圖過officers 。

 var officers = [ { id: 20, name: 'Captain', lastName: 'Piett' }, { id: 24, name: 'General', lastName: 'Veers' }, { id: 56, name: 'Admiral', lastName: 'Ozzel' }, { id: 88, name: 'Commander', lastName: 'Jerjerrod' } ]; var officersIds = officers.map(x => [["x", "y"], [x.name, x.lastName]]); console.log(officersIds);

Answer 3

如果您只想將['x', 'y']到數組的開頭，您可以使用擴展運算符使其成為單行：

var officersIds = [['x', 'y'], ...officers.map(x => [x.name, x.lastName])];

請參閱下面的概念驗證：

 var officers = [ { id: 20, name: 'Captain', lastName: 'Piett' }, { id: 24, name: 'General', lastName: 'Veers' }, { id: 56, name: 'Admiral', lastName: 'Ozzel' }, { id: 88, name: 'Commander', lastName: 'Jerjerrod' } ]; var officersIds = [['x', 'y'], ...officers.map(x => [x.name, x.lastName])]; console.log(officersIds);

---

但是，如果您想將['x', 'y']到數組中的每個項目，那么您應該這樣做：

var officersIds = officers.map(x => [['x', 'y'], [x.name, x.lastName]]);

 var officers = [ { id: 20, name: 'Captain', lastName: 'Piett' }, { id: 24, name: 'General', lastName: 'Veers' }, { id: 56, name: 'Admiral', lastName: 'Ozzel' }, { id: 88, name: 'Commander', lastName: 'Jerjerrod' } ]; var officersIds = officers.map(x => [['x', 'y'], [x.name, x.lastName]]); console.log(officersIds);

Answer 4

您可以將所需的部分添加到映射函數中。

 var officers = [{ id: 20, name: 'Captain', lastName: 'Piett' }, { id: 24, name: 'General', lastName: 'Veers' }, { id: 56, name: 'Admiral', lastName: 'Ozzel' }, { id: 88, name: 'Commander', lastName: 'Jerjerrod' }], officersIds = officers.map(x => [["x", "y"], [x.name, x.lastName]]); console.log(officersIds);