Keeping only alphanumerals in a JavaScript string in 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.

Therefore, let’s write the code for this function −


The code for this will be −

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];
      res += str[i].charCodeAt(0);
   return res;


The output in the console will be −

Th33s 33s 64 str33ng th64t cont6433ns some special characters3333

Updated on: 20-Oct-2020


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