Replacing all special characters with their ASCII value in a string - JavaScript

We are required to write a JavaScript function that takes in a string that might contain some special characters. The function should return a new string should have all special characters replaced with their corresponding ASCII value

Example

Following is the code −

const str = 'Th!s !s @ str!ng th@t cont@!ns some special characters!!';
const specialToASCII = str => {
   let res = '';
   for(let i = 0; i < str.length; i++){
      if(+str[i] || str[i].toLowerCase() !== str[i].toUpperCase() || str[i] === ' '){
         res += str[i];
         continue;
      };
      res += str[i].charCodeAt(0);
   };
   return res;
};
console.log(specialToASCII(str));

Output

This will produce the following output in console −

Th33s 33s 64 str33ng th64t cont6433ns some special characters3333