当值是数组时反转对象的键和值

Question

我有以下内容：

var object = {
    a: ["A1"],
    b: ["B1", "B2"],
    c: ["C1", "C2", "C3", "C4"]
};

我想将上面的转换为：

var result = {
    A1: "a",
    B1: "b",
    B2: "b",
    C1: "c",
    C2: "c",
    C3: "c",
    C4: "c"
};

我是 Javascript 的新手。有什么有效的方法可以做到这一点？如果需要，我可以导入其他库并假设数组中的值是唯一的。谢谢

Answer 1

试试这个，

var object = {
  a: ["A1"],
  b: ["B1", "B2"],
  c: ["C1", "C2", "C3", "C4"]
};
var keys = Object.keys(object);
var obj = {};
for(var j=0,l=keys.length;j<l;j++){
  for (var i = 0; i < object[keys[j]].length; i++) {
    obj[object[keys[j]][i]] = keys[j];
  }
}
console.log(obj);

var object = {
  a: ["A1"],
  b: ["B1", "B2"],
  c: ["C1", "C2", "C3", "C4"]
};
var keys = Object.keys(object);
var obj = {};

for(var j=0,l=keys.length;j<l;j++){
  for (var i = 0; i < object[keys[j]].length; i++) {
    obj[object[keys[j]][i]] = keys[j];
  }
}
console.log(obj);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

Answer 2

具有 forEach 和 arrow 函数的解决方案（ES6 标准）

var object = { a: ["A1"], b: ["B1", "B2"], c: ["C1", "C2", "C3", "C4"] };

var result = {};

Object.keys(object).forEach(k =>
    object[k].forEach(a => result[a] = k));

document.write('<pre>' + JSON.stringify(result, 0, 2) + '</pre>');

当值是数组时反转对象的键和值

Invert the key and value of an object while the value is an array

javascript

jquery

node.js

underscore.js