Question

有没有办法可以在给定int值的情况下打印枚举字段的值？例如，我有以下枚举：

refractiveIndex = {"vacuum": 1, "air": 1.000293, "water": 1.33, "diamond": 2.419};

如果我有值，有没有办法打印枚举的名称。例如，假设我将变量设置为1，我想打印出＆＃34; vacuum＆＃34;，我该怎么做：

var value = 1;
console.log(refractiveIndex(value)); // Should print "vacuum" to console

Answer 1

您可以迭代密钥并针对属性的值进行测试。

＆＃13;

var refractiveIndex = {"vacuum": 1, "air": 1.000293, "water": 1.33, "diamond": 2.419},
    value = 1,
    key;

Object.keys(refractiveIndex).some(function (k) {
    if (refractiveIndex[k] === value) {
        key = k;
        return true;
    }
});
console.log(key);

＆＃13;

ES6

＆＃13;

var refractiveIndex = {"vacuum": 1, "air": 1.000293, "water": 1.33, "diamond": 2.419},
    value = 1,
    key = Object.keys(refractiveIndex).find(k => refractiveIndex[k] === value);

console.log(key);

＆＃13;

Answer 2

https://jsfiddle.net/1qxp3cf8/

用于...浏览对象属性并检查它是否等于您要查找的值。

refractiveIndex = {
  "vacuum": 1,
  "air": 1.000293,
  "water": 1.33,
  "diamond": 2.419
};

var value = 1;
for (prop in refractiveIndex) {
  if (refractiveIndex[prop] == value) {
    console.log(prop);
  }
}

如果你想把它作为一个函数你可以写成：

function SearchRefractive(myValue) {
    for (prop in refractiveIndex) {
      if (refractiveIndex[prop] == myValue) {
        return prop;
      }
    }
}
var value = 1;
SearchRefractive(value);

Javascript - 从值打印枚举的名称

2 个答案: