Function does not work when entering number javascript-CodePudding

I have a function that reverses a string. I would like the function to return "Null" when a number is entered however when i input a number my function stops working. Is there something i am missing?

function reverseWords(words) {
    let eachLetter = words.split("");

    let reverseLetter = eachLetter.reverse();

    let combineLetter = reverseLetter.join("");

    if (typeof words !== "string") {
        return null;
    } else {
        return combineLetter;
    }
}

console.log(reverseWords(89));

CodePudding user response：

the operations you try to perform before the if are not possible with numbers.

Put validation as the first thing your function does and everything will work.

CodePudding user response：

function reverseWords(words) {

if (typeof words !== "string") {
    return null;
} else {
        
   //Split the string 
  let eachLetter = words.split("");

  let reverseLetter = eachLetter.reverse();

  let combineLetter = reverseLetter.join("");


    return combineLetter;
}

}

console.log(reverseWords('89'));

You cannot apply 'split' method on numbers. First, check for the numeric value and perform the split function only when it is a string.