这两个涉及typeof的函数有什么区别

Question

我在 JavaScript 的老师给我布置了一个掌握函数的作业。我试图解决要求我像第二个代码一样输出的作业：

function showDetails(name = "unknown", age = "unknown", booleanez = "unknown") {
  let name22ez,num22ez,bool22ez;

  typeof booleanez === 'boolean'
    ? (bool22ez = booleanez)
    : typeof booleanez === "number"
    ? (bool22ez = age)
    : (bool22ez = name);

  typeof name === "string"
    ? (name22ez = name)
    : typeof name === "number"
    ? (name22ez = age)
    : (name22ez = booleanez);

  typeof age === "number"
    ? (num22ez = age)
    : typeof age === "string"
    ? (num22ez = name)
    : (num22ez = booleanez);
  return `Hello ${name22ez}, Your Age Is ${num22ez}, You ${
    bool22ez === true ? bool22ez =`Are` : bool22ez = `Are Not`
  } Available For Hire`;
}

document.write(showDetails("Osama", 38, true));
document.write(`<hr>`);
document.write(showDetails(38, "Osama", true));
document.write(`<hr>`);
document.write(showDetails(true, 38, "Osama"));
document.write(`<hr>`);
document.write(showDetails(false, "Osama", 38));

输出为：

Hello Osama, Your Age Is 38, You Are Available For Hire
Hello Osama, Your Age Is 38, You Are Available For Hire
Hello Osama, Your Age Is 38, You Are Available For Hire
Hello 38, Your Age Is false, You Are Available For Hire

我尝试了很多次，大约 4 个小时，修复它，但我没有这样做，我从另一个学生那里得到了答案，他的答案是这样的：

function checkStatus(a, b, c) {
    let str, num, bool;
    typeof a === "string"
        ? (str = a)
        : typeof b === "string"
        ? (str = b)
        : (str = c);
    typeof a === "number"
        ? (num = a)
        : typeof b === "number"
        ? (num = b)
        : (num = c);
    typeof a === "boolean"
        ? (bool = a)
        : typeof b === "boolean"
        ? (bool = b)
        : (bool = c);
    return `Hello ${str}, Your Age Is ${num}, You ${
        bool ? "Are" : "Are Not"
    } Available For Hire`;
}

document.write(checkStatus("Osama", 38, true));
document.write(checkStatus(38, "Osama", true));
document.write(checkStatus(true, 38, "Osama"));
document.write(checkStatus(false, "Osama", 38));

输出正确：

Hello Osama, Your Age Is 38, You Are Available For Hire 
Hello Osama, Your Age Is 38, You Are Available For Hire 
Hello Osama, Your Age Is 38, You Are Available For Hire 
Hello Osama, Your Age Is 38, You Are Not Available For Hire

我的代码和我同事的代码有什么区别？

Answer 1

原代码检查每个参数的类型。类型为string的参数用作姓名，类型为number的参数用作年龄，类型为boolean的参数用作可雇用性

你的条件逻辑让我完全摸不着头脑。每个三元组中的第一个测试是正确的——如果 booleanez 是布尔值，那么它应该用于 bool22ez。但其余的没有意义。如果 booleanez 是一个数字，为什么这意味着 age 参数应该分配给 bool2ez？

您需要使用与原始逻辑相同的逻辑，测试特定类型的每个参数，然后将其用作分配给需要该类型的变量的值。

  typeof booleanez === 'boolean'
    ? (bool22ez = booleanez)
    : typeof age === "boolean"
    ? (bool22ez = age)
    : (bool22ez = name);

并且由于您正在分配相同的变量，因此您应该只在分配的值部分使用三元组而不是重复要分配给的变量。

bool22ez = 
    typeof booleanez === 'boolean'
        ? booleanez
        : typeof age === "boolean"
        ? age
        : name;

Answer 2

要添加到，这是正确的代码：

function showDetails(name = "unknown", age = "unknown", booleanez = "unknown") {
  let name22ez,num22ez,bool22ez;

  typeof name === "string"
    ? (name22ez = name)
    : typeof age === "string"
    ? (name22ez = age)
    : (name22ez = booleanez);
  typeof age === "number"
    ? (num22ez = age)
    : typeof name === "number"
    ? (num22ez = name)
    : (num22ez = booleanez);
  typeof booleanez === 'boolean'
    ? (bool22ez = booleanez)
    : typeof name === "boolean"
    ? (bool22ez = name)
    : (bool22ez = age);
  return `Hello ${name22ez}, Your Age Is ${num22ez}, You ${
    bool22ez === true ? bool22ez =`Are` : bool22ez = `Are Not`
  } Available For Hire`;
}

Answer 3

抱歉打扰了您 post 的评论部分。我的观点是，编写此函数的更明智的方法是：

function showDetails(details) {
  // do some type checking up here for the existence of the values
  // because JavaScript is not a strongly typed language
  // ...
  // return the result if the details are provided
  return `Hello ${details.name}, Your Age Is ${details.age}, You ${details.forHire ? 'Are' : 'Are Not'} Available For Hire`;
}

console.log(showDetails({
  name: 'Osama',
  age: 38,
  forHire: true
}))

console.log(showDetails({
  name: 'Osama',
  age: 38,
  forHire: false
}))

不过，请听@Barmar 专门针对您的作业。

Answer 4

即使我非常同意 Barmar 所说的 这完全是愚蠢的。头脑正常的人都不会写这样的代码。，我只是喜欢那些挑战。

看看如果我是你我会建议的解决方案：

function showDetails(name = "unknown", age = "unknown", booleanez = "unknown") {
  
  // Accept specific types and one of each
  let acceptedTypes = ["string", "number", "boolean"];
  let typeSet = Array.from(new Set([typeof name, typeof age, typeof booleanez]));
  if (typeSet.length != 3) {
    return "ERROR - I need 3 different types of argument.";
  }
  for (let i = 0; i < typeSet.length; i++) {
    if (acceptedTypes.indexOf(typeSet[i]) == -1) {
      return "ERROR - At least one argument is not accepted.";
    }
  }
  
  // Beyond this point, proceed!
  let args = [
    { type: typeof name, value: name },
    { type: typeof age, value: age },
    { type: typeof booleanez, value: booleanez }
  ];

  // Expecting in this order: "string", "number", "boolean"
  // which are in the reversed alphabetical order...
  // So use sort b-a on the types ;)
  args.sort((a, b) => b.type.localeCompare(a.type))

  return `Hello ${args[0].value}, Your Age Is ${args[1].value}, You Are ${args[2].value ? `` : `Not `}Available For Hire`;
}

console.log(showDetails("Osama", 38, true));
console.log(showDetails(38, "Osama", true));
console.log(showDetails(true, 38, "Osama"));
console.log(showDetails(false, "Osama", 38));
console.log(showDetails(0, "Osama", 38));
console.log(showDetails(0, "Osama", { age: 38 }));
console.log(showDetails());

这两个涉及typeof的函数有什么区别

What is the difference between these two functions involving typeof

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