根据另一个变量的数据类型转换一个变量

Question

我想要一个基于“引用”类型变量转换变量的函数。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，如果 ref 是 bigint

，我只能将数字转换为 bigint

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

最好将一个变量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

根据另一个变量的数据类型转换一个变量

Cast a variable based on the data type of another variable

javascript

types

casting