Arrow function that expects 2 numbers and returns undefined if they aren't numbers-CodePudding

Need help. Need an arrow function that expects 2 numbers as input (e.g. 1, 2) and returns the sum of the two numbers. If anything other than 2 numbers is passed, return undefined. Not sure where I'm going wrong on this.

const sum = (num1, num2) => {
    
if((num1.value !== 0)||(num2.value !== 0)){
    return undefined
}
    return num1   num2
}
console.log(sum(4,4))

Just keeps returning undefined, and doesn't go to finding sum.

CodePudding user response：

Use isNaN

const sum = (num1, num2) => {
  if (isNaN(num1) || isNaN(num2)) {
    return undefined;
  }
  return num1   num2;
};
console.log(sum(4, 4));

CodePudding user response：

You are trying to access a submember of a number value, not an object, so you will always get something you don't want to get. This should work better :

const sum = (num1, num2) => {
if(isNaN(num1) || isNaN(num2)){
    return undefined
}
    return num1   num2
}
console.log(sum(4,4))

You should also look what is isNaN which is a better way to check if you do receive a number or not :) https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/isNaN

CodePudding user response：

I think what are are looking for is something like this.

const sum = (num1, num2) => {
    if (typeof(num1) !== "number" || typeof(num2) !== "number")
        return "undefined";

    return num1   num2;
}