这两个涉及typeof的函数有什么区别

Question

我的JavaScript老师给了我一个主函数的作业。我试图解决要求我像第二个代码一样输出的任务：

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 

我试了很多次，大约4个小时，试图修复它，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：

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

原始代码检查每个参数的类型。类型为string的参数用作名称，类型为数字的参数用作年龄，类型为布尔值的参数用作可雇佣性。

你的条件逻辑让我很困惑。每个三进制中的第一个测试是正确的——如果booleanez是布尔的，那么它应该用于bool22ez。但其余的都没有意义。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，针对特定类型测试每个参数，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);

既然你分配的是同一个变量，你应该在赋值的值部分使用三进制，而不是重复要分配的变量。

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

Answer 2

很抱歉破坏了您文章的评论部分。我的观点是，编写这个函数的一种更明智的方法是：

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，具体到你的任务，请听@Barmar。

Answer 3

要添加到Barmar的答案中，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 4

即使我非常同意Barmar说的这完全是愚蠢的。没有一个头脑正常的人会写这样的代码，我只是喜欢这些挑战。

如果我是你，看看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());