将函数传递给函数和不同长度的参数

Question

我有两个功能：

first - takes 1 argument
secon - takes 2 arguments

然后我有第三个函数，它接收一个函数和一个值作为参数。

我无法弄清楚如何让第三个函数知道它正在接收一个参数或两个参数，具体取决于在第二个参数中传递的函数？？？

**在下面的示例中，当调用第三个时，它应该在代码末尾的两个调用中返回 2。

let val = 12;

let val2 = 14
let toC = 14;

// checks if val === 12 | takes 1 argument
const first = num => num === 12 ?2 :0;

// checks if val === toC | takes 2 arguments
const second = (num, check) => num === check ?2 :0;

// third function that receives a function and a val as arguments
const third = (func, num) => {
  let temp = func(num);
  return temp;
}

// this one works
console.log(third(first, val));

// this doesn't
console.log(third(second, (val2, toC)));

Answer 1

看起来third 函数只是为了调用作为参数提供的函数并返回值。在这种情况下，您可以使用rest parameters。

let val = 12;

let val2 = 14
let toC = 14;

// checks if val === 12 | takes 1 argument
const first = num => num === 12 ? 2 :0;

// checks if val === toC | takes 2 arguments
const second = (num, check) => num === check ?2 :0;

const third = (func, ...args) => {
  let temp = func(...args);
  return temp;
}


console.log(third(first, val));

console.log(third(second, val2, toC));