将多个键匹配到单个值的最简洁方法？ [复制]

Question

将多个键与 1 个值匹配的最简洁方法是什么？例如在 jQuery Validate 我有类似的东西：

$("#myform").validate({
  rules: {
    firstname: "required",
    middlename: "required",
    lastname: "required"
  },
  messages: {
    firstname: "Please fill in first name",
    middlename: "Please fill in middle name",
    lastname: "Please fill in last name"
  }
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script type="text/javascript" src="http://code.jquery.com/jquery-1.11.1.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery-validate/1.19.1/jquery.validate.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery-validate/1.19.1/additional-methods.js"></script>


<form id="myform">
  <div>
    <label for="firstname">First Name</label>
    <input type="text" id="firstname" name="firstname">
  </div>
  <div>
    <label for="middlename">Middle Name</label>
    <input type="text" id="middlename" name="middlename">
  </div>
  <div>
    <label for="lastname">Last Name</label>
    <input type="text" id="lastname" name="lastname">
  </div>
  <input type="submit" value="Search">
</form>

这很好，但我觉得重复firstname: "required"、middlename: "required"、lastname: "required" 是没有必要的，我怎样才能有多个匹配相同值的键可能像这样？

var names = {firstname, middlename, lastname};
$("#myform").validate({
  rules: {
    names: "required"
  },
  messages: {
    firstname: "Please fill in first name",
    middlename: "Please fill in middle name",
    lastname: "Please fill in last name"
  }
});

我知道我可以使用 for 循环，但我正在寻找最简洁的方式。

Answer 1

自己使用$.each()想出了一个解决方案，它基本上是匹配具有相同值的不同键。

var rule = "required",
    message = "Please fill in this field",
    fields = ["firstname", "middlename", "lastname"],
    rules = {},
    messages = {};

// assign "required" to each key of fields 
$.each(fields, function (index, value) {
  rules[value] = rule;
  messages[value] = message;
});

$("#myform").validate({
  rules: rules,
  messages: messages
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery-validate/1.19.1/jquery.validate.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery-validate/1.19.1/additional-methods.js"></script>

<form id="myform">
  <div>
    <label for="firstname">First Name</label>
    <input type="text" id="firstname" name="firstname">
  </div>
  <div>
    <label for="middlename">Middle Name</label>
    <input type="text" id="middlename" name="middlename">
  </div>
  <div>
    <label for="lastname">Last Name</label>
    <input type="text" id="lastname" name="lastname">
  </div>
  <input type="submit" value="Search">
</form>