根据另一个变量的数据类型强制转换一个变量

Question

我想要一个函数，它根据变量的"参考"；类型变量。我猜该函数将采用两个参数cast(x, ref)，其中x是根据ref的数据类型进行强制转换的变量。例如：

let myVar = cast(3, "helloworld");
console.log(myVar); // "3"
let myNewVar = cast(myVar, 32423n);
console.log(myNewVar); // 3n

现在，我只成功地将数字转换为bigint，如果ref是bigint

const cast = (n, ref) => typeof ref === "number" ? n : BigInt(n)

最好将一个变量强制转换为另一个变量的数据类型。

Answer 1

// Cast will attempt to force cast something (n) into the type of
// something else (ref)
const cast = (n, ref) => {
switch(typeof(ref)) // All major types and how to convert them
{
case "boolean": return Boolean(n);
case "number": return Number(n);
case "bigint": return BigInt(n);
case "string": return String(n);
case "symbol": return Symbol(n);
case "undefined": return undefined;
default: return n; // If none of the above is the type, we return n
}
}
// Example: 2 is an int, and the reference is a string, so we cast an int 
// to a string, this could be done with various types more complexly
let a = 2
let b = "hello"
a = cast(a, b)
console.log(a, typeof(a)) // 2, string