javascript - 如何在 JavaScript 中对数组进行 switch() ？

Question

我有一个空数组，如下所示:

var itemsWithEmptySockets = [];

可能会填充以下一个或多个值(取决于通过 n API 提取的信息):

0, 1, 2, 4, 5, 6, 7, 8, 9, 15, 16

地点:

0 = Head
1 = Neck
2 = Shoulder
4 = Chest
5 = Waist
6 = Legs
7 = Feet
8 = Wrist
9 = Hands
14 = Back
15 = MainHand
16 = SecondaryHand

我想测试一下数组中的内容，并通过将字符串存储在数组中将这些数字本质上转换为字符串，例如如果为 0，则 Head 有一个空套接字，将“Head”添加到新数组中，然后我想用它在 DOM 中将“Head”显示为字符串。

为了做到这一点，我尝试了一个 switch 语句，例如

switch(itemsWithEmptySockets){
case 0:
emptyItems.push("Head");
break;

但是 switch 语句似乎不支持以这种方式使用数组，即传递数组 itemsWithEmptySockets。

有没有比 12 个 if 语句更有效的方法？例如

for(i=0; i < itemsWithEmptySockets.length; i++){
    if(itemsWithEmptySockets[i] == 0){
      emptyItems.push("Head");
    }
if(itemsWithEmptySockets[i] == 1){
      emptyItems.push("Neck");
    }
etc.
}

非常感谢您的帮助!

Answer 1

我认为我不会为此使用 switch ；我会使用映射对象:

// In one central place
var socketMappings = {
    0: "Head",
    1: "Neck",
    2: "Shoulder",
    4: "Chest",
    5: "Waist",
    6: "Legs",
    7: "Feet",
    8: "Wrist",
    9: "Hands",
    14: "Back",
    15: "MainHand",
    16: "SecondaryHand"
};

// Where you're doing this
var emptyItems = [];
itemsWithEmptySockets.forEach(function(entry) {
    emptyItems.push(socketMappings[entry]);
});

实例:

// In one central place
var socketMappings = {
  0: "Head",
  1: "Neck",
  2: "Shoulder",
  4: "Chest",
  5: "Waist",
  6: "Legs",
  7: "Feet",
  8: "Wrist",
  9: "Hands",
  14: "Back",
  15: "MainHand",
  16: "SecondaryHand"
};

// Where you're doing this
itemsWithEmptySockets = [
  0,
  14,
  5
];
var emptyItems = [];
itemsWithEmptySockets.forEach(function(entry) {
  emptyItems.push(socketMappings[entry]);
});

// Show result
snippet.log(itemsWithEmptySockets.join(", "));
snippet.log(emptyItems.join(", "));

<!-- Script provides the `snippet` object, see http://meta.stackexchange.com/a/242144/134069 -->
<script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script>

或者，如果 emptyItems 中还没有任何其他内容，请使用 Array#map:

// In one central place
var socketMappings = {
    0: "Head",
    1: "Neck",
    2: "Shoulder",
    4: "Chest",
    5: "Waist",
    6: "Legs",
    7: "Feet",
    8: "Wrist",
    9: "Hands",
    14: "Back",
    15: "MainHand",
    16: "SecondaryHand"
};

// Where you're doing this
var emptyItems = itemsWithEmptySockets.map(function(entry) {
    return socketMappings[entry];
});

实例:

// In one central place
var socketMappings = {
  0: "Head",
  1: "Neck",
  2: "Shoulder",
  4: "Chest",
  5: "Waist",
  6: "Legs",
  7: "Feet",
  8: "Wrist",
  9: "Hands",
  14: "Back",
  15: "MainHand",
  16: "SecondaryHand"
};

// Where you're doing this
itemsWithEmptySockets = [
  0,
  14,
  5
];
// Where you're doing this
var emptyItems = itemsWithEmptySockets.map(function(entry) {
  return socketMappings[entry];
});

// Show result
snippet.log(itemsWithEmptySockets.join(", "));
snippet.log(emptyItems.join(", "));

<!-- Script provides the `snippet` object, see http://meta.stackexchange.com/a/242144/134069 -->
<script src="http://tjcrowder.github.io/simple-snippets-console/snippet.js"></script>