使用开关接收未知数据类型，发出接收对象的问题

Question

在下面的代码中，我试图创建一个switch语句，该语句接受以下输入:34，'34'，{input:34}，hello，[“hello”]

并在每个输入中返回数字34，则我需要具有的大小写为:

If given a number, return the number
If given a string, convert it to a number and return the result
If given an object, return the value of the input property
Otherwise, throw an error: "Unexpected data type"

我的对象输入有问题。太谢谢你了！

function parseNumber(unknown) {
  switch(unknown) {
    case 34:
        return unknown;
    
    case '34':
        return parseInt(unknown);
      
    case unknown.input: 
        return unknown.input;
    
    default:
        throw new Error("Unexpected data type");
  }
}

Answer 1

在开关情况下，可以使用typeof结果来确定输出:

null

js prettyprint-override">/*If given a number, return the number
If given a string, convert it to a number and return the result
If given an object, return the value of the input property
Otherwise, throw an error: "Unexpected data type"*/


function parseNumber(unknown) {
  if (!unknown) throw new Error("Unexpected data type");
  const type = typeof unknown;
  switch (type) {
    case "number":
      return unknown;
    case "string":
      return +unknown;
    case "object" && !Array.isArray(unknown):
      return unknown.input;
    default:
      throw new Error("Unexpected data type");
  }
}
console.log(parseNumber(34));
console.log(parseNumber('34'));
console.log(parseNumber({input: 34}));
//Error cases
console.log(parseNumber());
console.log(parseNumber(() => "hello"));
console.log(parseNumber([34]));